What is Banquo's fatal flaw in Macbeth?

What an interesting question! I think Banquo's fatal flaw seems to be that he happened to stumble upon the witches with Macbeth. The witches hail both of the men, with prophecies for each. They tell Macbeth that he shall be king. Seeing Banquo, they do not leave him out: they say that his descendants will be kings. The witches' prophesies are important for two reasons.

First, the fact that Banquo's descendants will be kings makes Macbeth feel threatened. He wants to dispatch of Banquo and Fleance. Would Macbeth even hear this prophecy if Banquo were not in front of the witches? They only address Banquo when they see him, so perhaps if Macbeth was walking alone or with someone else, they would not have mentioned the destiny of Banquo's line, and therefore Macbeth would not feel threatened by it.

Secondly, being with Macbeth at the time, Banquo knows of the prophecy that Macbeth will be king. While Macbeth is on his way to kill Duncan, he runs into Banquo. Banquo says to Macbeth,

I dreamt last night of the three weird sisters:
To you they have show'd some truth.

Macbeth brushes off that he hasn't given them thought, but Banquo's quote shows that he is thinking of how the prophecy has come true in the sense that Macbeth has become the Thane of Cawdor. He has the potential to suspect Macbeth after Duncan's murder. This makes him a threat to Macbeth's safety, regardless of what happens with his sons. Indeed, he does have suspicions:

Thou hast it now: king, Cawdor, Glamis, all,
As the weird women promised, and, I fear,
Thou play'dst most foully for't: yet it was said
It should not stand in thy posterity,
But that myself should be the root and father
Of many kings. If there come truth from them—
As upon thee, Macbeth, their speeches shine—
Why, by the verities on thee made good,
May they not be my oracles as well,
And set me up in hope? But hush! no more.

Banquo has the power to contest Macbeth's crown, which puts him at risk. That, combined with the prophecy that his sons will be kings, make Macbeth hire murderers to kill both Banquo and Fleance.

What is Banquo's fatal flaw in Macbeth?

I would argue that two things are of importance when it comes to Banquo's death in the play. The first one pertains to the fact that Banquo is included in the witches' prophecy indirectly. Namely, the witches proclaim that Banqo's descendants will inherit the throne, which clashes with Macbeth's ambitions. Macbeth wants to become King of Scotland, yet, he does not want his bloody quest to eventually result in Banquo's descendants inheriting the throne:

 Upon my head they placed a fruitless crown,
 And put a barren sceptre in my gripe,
 Thence to be wrench'd with an unlineal hand,
 No son of mine succeeding. If 't be so,
 For Banquo's issue have I filed my mind;
 For them the gracious Duncan have I murder'd;
 Put rancours in the vessel of my peace
 Only for them; and mine eternal jewel
 Given to the common enemy of man,
 To make them kings, the seed of Banquo kings!

So, one reason why Macbeth kills Banquo is because of this.

The second thing that proves to be significant is when Macbeth tests Banquo in order to see whether he would be loyal to him at any cost. He discovers that Banquo is honorable and that he would be loyal to Macbeth as long as Macbeth's motives are pure. This convinces Macbeth that Banquo is a tangible threat to his ambitions.

Banquo's tragic flaw stems from the fact that despite realizing that Macbeth gained the throne unlawfully, he still pretends to be loyal to him. He also secretly hopes that his descendants will inherit the throne some day, just like the witches prophesied.

What is Banquo's fatal flaw in Macbeth?

In Shakespeare's classic play, Macbeth's tragic flaw is his "vaulting ambition," which leads him to murder King Duncan in his sleep, setting off a chain of events that culminates in Macbeth's demise. At the start of the play, Macbeth is portrayed as a loyal, courageous soldier, praised for his valiant performance on the battlefield in service of his king. On his way to Scone, Macbeth and Banquo meet three malevolent witches, who offer them mysterious prophecies.

The Three Witches address Macbeth as Thane of Glamis (his current title), Thane of Cawdor, and future King of Scotland. Shortly after Macbeth's perplexing interaction with the witches, Ross and Angus arrive and inform Macbeth that King Duncan has given him the title Thane of Cawdor as reward for his conduct in battle. With the first part of the witches' prophecy confirmed, Macbeth's ambition is awakened, and he remarks that he fears the "horrible imaginings" that now occupy his thoughts—in other words, he has already, somewhat unwillingly, begun to contemplate how he might take the throne from his king and fulfill the final part of the prophecy. Unsettled by the direction of his thoughts, he tries to put the matter from his mind.

However, when King Duncan officially names his son Malcolm as heir to the throne, granting him the title prince of Cumberland, Macbeth's ambition stirs once again. Noting that Malcolm is now another obstacle between him and the throne, Macbeth seems to already be forming a plan to seize the crown, even as he continues to war with himself, afraid of what he might be capable of:

The prince of Cumberland! That is a step
On which I must fall down, or else o’erleap,
For in my way it lies. Stars, hide your fires;
Let not light see my black and deep desires.
The eye wink at the hand, yet let that be
Which the eye fears, when it is done, to see (1.4.56–62).

Despite Macbeth's increasing desire to become king, he is reluctant to kill Duncan. He acknowledges that Duncan is a good and just ruler and admits that he has no legitimate reason to remove him from the throne. Macbeth fully realizes that the only thing motivating him to commit regicide is his ambition, and he knows very well that allowing himself to be led by ambition alone could be ruinous:

I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o’erleaps itself
And falls on th’ other (1.7.2526).

After much agonizing, Macbeth eventually succumbs to his ambition and assassinates the king—prodded along by his wife, Lady Macbeth, who is arguably even more ambitious than he. Macbeth is wracked with guilt after he kills Duncan in his sleep, and this act forever changes him. He soon degenerates into a desperate, bloodthirsty tyrant and is driven nearly mad by his fear of losing the throne. The once honorable Macbeth commits unspeakable acts—including ordering the death of his former friend Banquo and the murder of Macduff's wife and children—to stay in power. In the end, Macbeth's ambition causes him to lose everything, including his throne, his wife, his honor, and his life.

What is Macbeth's tragic or fatal flaw?

Macbeth, in the Aristotelian sense, does possess a fatal flaw.  For most who consider this question, it is his ambition, for others it is his want of power.  Both can be seen as similar for they both require increasing positions of power from Thane of Glamis, to Thane of Cawdor, to King.  His want of power motivates him to kill; his want of power motivates him to listen to his wife - who clearly questions his manhood, which, by extention, questions his sense of power for being a man meant being powerful. 

What is Macbeth's tragic or fatal flaw?

Macbeth's vaulting ambition, though it is what brings him to his height of power, it is also what leads him to his downfall. Vaulting Ambition is Macbeth's only flaw; it disables him to achieve his utmost goals and forces him to face his fate. Without this ambition, though, Macbeth never would have been able to achieve his power as King of Scotland or have been able to carry out his evil deeds. In these instances, ambition helped Macbeth do what he wanted to do. But, consequently, Macbeth's ambition has another face and is what leads him to his tragic downfall. Had he not been so enveloped with becoming King and remaining powerful, he would not have continued to kill innocent people in order to keep his position. It was because of these killings and his overbearing attitude that caused him to be overthrown and killed himself.

What is Macbeth's tragic or fatal flaw?

Macbeth is too easily led by others into sin.  He listens to the witches and their prophecies and begins hoping that something will happen that will allow him to become king.  Rather than stop there, he tells his wife, Lady Macbeth, what has been foretold, setting her determination and ambition into motion.  And rather than telling her to knock it off, Macbeth allows himself to be pushed into killing King Duncan and claiming the throne for himself.

Prior to the killing of Duncan, Macbeth could have stopped and said, "No, I'm going to do what I know to be right.  If I am meant to be king, then it will happen on its own."  Instead, he caves into the pressure from his wife (and his own ambition - he's not guiltless in this regard at all) and takes matters into his own hands - a dagger, to be exact!

What is Banquo's fatal flaw in Macbeth?

Macbeth's tragic flaw is his vaulting ambition, which motivates him to assassinate King Duncan and assume the title King of Scotland. After Macbeth initially hears the Three witches' prophecies and Ross tells him that he has been given the title Thane of Cawdor, Macbeth's mind begins to drift towards the possibility of becoming king. Macbeth reveals his ambitious nature by immediately thinking about murdering King Duncan. In act one, scene three, Macbeth says to himself,

"If good, why do I yield to that suggestion Whose horrid image doth unfix my hair And make my seated heart knock at my ribs, Against the use of nature? Present fears Are less than horrible imaginings" (Shakespeare, 1.3.137-141).

During Macbeth's soliloquy at the beginning of act one, scene seven, he contemplates the various reasons to not follow through with the murder and reveals that his ambition is the only thing motivating him to commit the crime. Macbeth says,

"I have no spur To prick the sides of my intent, but only Vaulting ambition, which o'erleaps itself And falls on th' other" (Shakespeare, 1.7.25-28).

Macbeth's ambition drives him to assassinate the king, which only results in more bloodshed as Macbeth desperately attempts to solidify and protect his title as king by killing his political enemies. While one could argue that Macbeth's pride influences him to challenge Macduff in the final battle, his ambition is certainly his tragic flaw, which serves as the catalyst for his fateful decision to commit regicide.

What is Banquo's fatal flaw in Macbeth?

Macbeth's fatal flaw seems to be ambition. After the three witches reveal the prophecy that Macbeth will one day be king, Macbeth and his wife hatch a plan to make sure that happens. The idea of murdering someone never entered Macbeth's mind until he heard about the possibility of being king.

In Act 1, Scene 7, Macbeth even admits that the only reason he has to kill King Duncan is ambition. He says, "I have no spur to to prick the side of my intent, but only vaulting ambition, which o'erleaps itself and falls on th' other."

Even after Macbeth kills King Duncan and becomes King of Scotland, his ambitions continue. He hires murderers to kill Banquo and his son Fleance because he wants to make sure his dynasty continues to his future son. 

All of the murderous decisions Macbeth makes in the play are a result of him wanting to be king, and then once he receives the crown, making sure he stays king and that it continues within his lineage. 

What is Macbeth's fatal flaw in William Shakespeare's Macbeth?

Macbeth is the protagonist of William Shakespeare's Macbeth, and the source of all his problems, his "fatal flaw," as you call it, is his ambition. 

When the witches indicate that Macbeth will one day be king and the first two predictions are realized, Macbeth is amazed, but already he is contemplating the possibility. 

[Aside] Glamis, and thane of Cawdor!
The greatest is behind.

In a moment, however, he again becomes the loyal soldier and says two things:

[Aside] If chance will have me king, why, chance may crown me,
Without my stir.

[Aside] Come what come may,
Time and the hour runs through the roughest day.

It appears that Macbeth is resigned to waiting for the day when he assumes he will become king; but his ambition is just below the surface. Unfortunately for Macbeth, in the next scene, King Duncan pronounces that his son, Malcolm, will be his heir. Now things change for Macbeth, and he says:

[Aside] The Prince of Cumberland! that is a step
On which I must fall down, or else o'erleap,
For in my way it lies.

There it is, the ambition which will go on to cause Macbeth to kill the king, his best friend, and anyone else who seems to be against him (for he becomes quite suspicious and paranoid) in order to get and keep his power. 

Macbeth's ambition (which causes him to kill Duncan) vaults him to the throne, but it is also the thing that kills him. Scotland is suffering at his hands because he is concerned only about maintaining his position. When he sees the witches one last time, they make him more promises, which, in his arrogance and blind ambition, he chooses to believe. If he had not assumed that no one could kill him, Macduff might not have been able to do it.

Macbeth's ambition, as well as that of his wife, is what steals the throne for him; he is unworthy to be king but remains in the position until his ambition and arrogance finally lead to his death. Ambition coupled with arrogance is Macbeth's "fatal flaw."

What is the character flaw that is the cause of Macbeth's downfall?

I agree with ambition, but I want to throw pride in there too.  How does Lady Macbeth get him to kill Duncan?  She question his manhood.  She does this repeatedly.  She even says she's more of a man than he is (the speech about her dashing out her baby's brains).  Then, after Macbeth visits the witches again, hears what they have to say, and sees the apparitions, he foolishly believes himself invinsible.  All men are born of women.  How can woods march?  He thinks himself safe. 

In ancient Greek tragedies, hubris (too much pride) cause many a hero's downfall.  I think it is true of Macbeth too.

What is the character flaw that is the cause of Macbeth's downfall?

Certainly the traditional notion is that the cause of Macbeth's downfall is his ambition. And there is no question that much of what Macbeth does is caused by a need to better his position. As Lady Macbeth says of her husband,

Thou wouldst be great;

Art not without ambition, but without

The illness should attend it,

So yes, he has ambition, but his fatal fault is alluded to in the last line: he doesn't have the "illness" that needs to come with it. He doesn't have the burning desire, the obsession necessary to drive him to do what has to be done in order to be powerful and great. Not yet.

The witches and Lady Macbeth together push him over the edge of his own reticence, his inherent heroism and goodness, and they get him to do things that are not really in his nature. It is his weak-mindedness, his easy susceptibility to suggestion and temptation that is his tragic flaw. That's why, once he sets out on the path of murder, he can't take it; he is overcome by guilt, fear and paranoia excacly because killing for personal gain is not in his nature. Lady Macbeth, who knows her husband, is right when she says:

What thou wouldst highly,

That wouldst thou holily; wouldst not play false,

And yet wouldst wrongly win. Thou'ldst have, great Glamis,

That which cries, “Thus thou must do, if thou have it;

And that which rather thou dost fear to do

Than wishest should be undone.”

What I believe, and I grant that I may be quite alone in this view, is that Macbeth is a good man and a brave and stout warrior, who, to his ultimate, tragic downfall, is too easily manipulated, and, strong as he may be in other ways, he is very weak when faced with the trickery, prodding and chastisement of... hold on to your hats: women.

What is the character flaw that is the cause of Macbeth's downfall?

Shakespeare's plays are usually put into one of several categories: Tragedy (such as "Macbeth"), Comedy (such as "All's Well That Ends Well"), History (Such as "Richard III'), Pastoral (such as "As You Like It"), or Romance (such as "The Tempest").

In each of these genres, Shakespeare observes and comments on the human condition. In essence, nothing much has changed about human beings AS human beings from the Elizabethan era, during which he lived and worked, to our own.

The category, "Tragedy", contains Shakespeare's "Macbeth", "King Lear", "Antony and Cleopatra", et al.  In each of these, the true "tragedy" can be said to be a human flaw which sets into motion and/or keeps in motion the events which result in disaster. These character flaws have existed since time immemorial, exist in each of us today, and will likely continue to exist as long as the human race endures.

Human flaws might also be called tragic flaws, character flaws, human inadequacies, or a host of other names. By examining ourselves and those around us, we will surely observe such factors in our lives as greed, hubris, dishonesty, untrustworthiness, etc.  We can also readily understand that such flaws within us contribute mightily to the state of war, the economic state, the moral state, and the state of humanity which plague us in our own time and place.

With the above as introduction and background, one can understand that Macbeth's greatest human frailty, his vaulted flaw, the tragic fiber within him which drove him to his horrible deeds, was greatly excessive ambition.

Ambition can be a desirable characteristic in any of us.  Without ambition, we would remain complacent in such mundane activities as cleaning house, bathing, preparing healthful meals, etc.  A lack of ambition would have an even greater effect on our going beyond the most basic requirements in our studies, or being willing to remain the person lowest in rank and most poorly paid in our careers.  At the highest levels, no ambition would lead us not to have sufficient desire and drive to work for peace, or strive to cure disease, or to show compassion to our fellow man.

But ambition can also be a dangerous thing.  It was ambition which caused the break in at the Watergate Hotel and brought an American president to the shame of resignation.  It was religious ambition which brought about the horrifying events of "9/11". Political and military ambition has most often been the defining factor in bringing nations into war.

It was this same kind of "ambition on steroids", one might say, which caused Macbeth to hasten events which would have likely happened anyway, had he had the patience to await them. But, without patience, and with an ambition that was clearly out of control, he brought about horrendous evil, including the most dreadful crime of murder.

Shakespeare understood the human condition, in my opinion, better than any other writer of his or any other time.  His studies and observations in the same have resulted in plays of great power and insight.

What is the character flaw that is the cause of Macbeth's downfall?

To me, the major character flaw that brings Macbeth to his downfall is ambition.  His ambition is combined with a lack of morality in his character to make him end up losing everything he was trying to gain.

To be a great hero in the days in which the play is set, a man had to be very ambitious.  You did not get to be a strong leader without really wanting to.  So clearly Macbeth's ambition is what has made him great.

But his ambition will also bring him down because it will cause him to go a step too far.  It will cause him to kill Duncan and that is the beginning of the end for him.

What is the tragic flaw of Macbeth according to Aristotle?

What is the tragic flaw of Macbeth according to Aristotle?

What is the tragic flaw of Macbeth according to Aristotle?

I think Macbeth, like Shakespeare's other tragic heroes, did have a fatal flaw, but I agree it was his actions that brought him down. That's the way it works, I think, in life as well as in literature. Macbeth's flaw is ambition. It was there. It had always been there, but he didn't know it. Between the time he hears the prophecies and the time Duncan is actually killed, Macbeth talks a lot about his ambition--his "deep desires" as if he hadn't noticed them before, but, wow, here they are. Aren't they awful.

That seems to be another part of Shakespeare's heroes. They don't realize until too late what has done them in. Macbeth didn't know he was ambitious; Othello didn't recognize that he had no sense of self-worth; Lear didn't realize that he was a vain and foolish old man; Brutus thought the rest of the world lived according to his ideals; and Hamlet had never had to make a major adult decision before, so he had never found out he was indecisive.

But back to Macbeth. Ambition lay buried inside him, dormant. The prophecies woke it up, as it were, and Lady Macbeth poured fuel on the flame. Once Macbeth had acted on his ambition by killing Duncan, his soul was lost and he knew it and he didn't need any further prodding from his wife. He was quite capable at that point of committing the rest of his heinous acts without prompting, trying to hold on to what he had paid too high a price to obtain.

So . . .  I think Macbeth did indeed have a fatal flaw which prompted his actions that led to his downfall.

What is the tragic flaw of Macbeth according to Aristotle?

Well, let's first get the chicken before the egg, so to speak...

Aristotle set forth the criteria of Greek tragedy long before Shakespeare's "Macbeth" (even prior to the stories on which the play was based).  The idea of "tragic flaw" was that one weakness in an otherwise almost perfect hero brought about his undoing or "fall," thus making the idea of tragedy or loss even worse.

Shakespeare's "Macbeth" adheres to the criteria of Greek tragedy (as set forth by Aristotle) in that the character Macbeth let ambition get the best (and finally worst!) of him, bringing about his ultimate downfall.

What is the tragic flaw of Macbeth according to Aristotle?

I'm sorry to seem pedantic, but it's so important to be strict about this. Aristotle never wrote about tragic flaws. Hamartia is the Greek word usually mis-translated as "tragic flaw". It actually means "mistake".

Aristotle's conception of tragedy involves a man of high status who makes a mistake, and therefore falls to lower status and disgrace. It also makes a lot more sense that people do something wrong, rather than just are fundamentally wrong in the first place.

"Macbeth" undoubtedly fits this pattern, and, rather than have to scrabble about pointlessly to find a "tragic flaw", you can instead point to a very definite mistake. Macbeth, because of the witches, his wife, and his own ambition (all three of them play a part, I think!) kills the king. It's downhill from there.

What is Banquo's fatal flaw in Macbeth?

Macbeth's most crucial flaw is his ambition. It drives him to commit unnatural and evil deeds to fulfill the witches' prophecy as he understands it. At the beginning of the play Macbeth is described by his peers as a virtuous and loyal thane to the king, his kinsman Duncan. But as soon as he encounters the witches and hears their prophecy that he will become king, he is consumed by what he calls his "black desires." He acknowledges his own ambition when he vacillates over murdering Duncan, admitting that he has no cause to kill the king except his own ambition:

I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other...

The problem with Macbeth's ambition is that it drives him to rise above his place in society. It upsets the natural order of things, and unleashes a flood of violence that consumes Scotland. 

Another of Macbeth's flaws is his willingness to listen and to be directed by others. His wife, convinced that Macbeth might be too "full of the milk of human kindness" to carry out the brutal deeds necessary to fulfill what she sees as his destiny, challenges his masculinity and his courage to goad him into killing Duncan when he hesitates. Macbeth also places total faith in the witches, which causes him to interpret their cryptic prophecies in ways that turn out to be misguided. For example, he believes that the witches' statement that he can never be killed by anyone "of woman born" causes him to be overconfident, and when he discovers that Macduff was born by Caesarian section, thus technically fulfilling the prophecy, he feels that unnatural forces have tricked him. Still, it must be said, he allowed himself to be tricked, and doing so brought him to the fateful meeting with Macduff outside Dunsinane. 

How does Macbeth's fatal flaw in Macbeth contribute to his downfall?

Arguably, Macbeth's fatal flaw is his ambition, which, it is suggested in Act I scene 3, has already caused him to think about murdering Duncan and seizing the crown. This is something that makes him easy prey for the witches and their manipulation and prophecies. What makes Macbeth's downfall even more tragic, however, is the way that he recognises that ambition is his own tragic flaw, but then leaves himself open to the manipulation of another character--this time his own wife. Note what he says in his soliloquy in Act I scene 7:

I have no spur

To prick the sides of my intent, but only

Vaulting ambition, which o'erleaps itself

And falls on th'other--

The image is of somebody who tries to mount a horse so enthusiastically, that they end of missing the horse completely and landing on the floor on the other side. So too, Macbeth sees the danger of himself trying to achieve more than he can reasonably gain through his ambition, and hurting himself in the process. The irony is of course that Macbeth is correct: he ends up losing far more than he ever had. However, it is his ambition to not only be King of Scotland, but then also to ensure that he does not lose that title for his descendants, that drives him to his various excesses.

If Macbeth has a tragic flaw, what is it?

Macbeth, the protagonist in William Shakespeare's play Macbeth, does have a tragic flaw. Essentially, even if one cannot recognize Macbeth's flaw, one must exist based upon the characteristics of the tragic play.

Given that Macbeth has been historically identified as a tragic play, one characteristic of the tragic play is that the "protagonist must be an admirable but flawed character." This tragic flaw is called hamartia.

Even with that being said, one can identify Macbeth's tragic flaw through examining what caused his downfall. Macbeth dies at the end. Prior to his death, Macbeth kills many people. One of the people who Macbeth kills is Duncan. Duncan is the current king. Prior to killing Duncan, Macbeth is ridiculed by his wife based upon the prophecies he heard from the witches (that he will be king). When one backtracks through the play, they are led to this thought/question: why did Macbeth kill the king (which led to,in the end, the death of Macbeth)?

Essentially, Macbeth killed the king because he wanted the throne. He did not stick by his initial thoughts about the throne (seen in I,iii):

If chance will have me king, why, chance may crown me. Without my stir. 

Therefore, it was his tragic flaw, his growing ambition, which led to his downfall.

In Macbeth, what—in one word—is Macbeth's character flaw?

Macbeth's character flaw, in a single word, is greed. (In more than one word, it would be unfettered political ambition.) Greed, by definition, means the selfish desire to acquire something, a desire that surpasses all reason. It is Macbeth's overwhelming, selfish desire to gain the throne and rule Scotland that drives him to murder Duncan. Macbeth violates his own conscience and knowingly sacrifices his soul to wear Duncan's crown. His greed--he would have not some power as Thane of Glamis and Thane of Cawdor, but all power--destroys him. Once Macbeth is crowned, he continues to murder, again and again, to maintain his hold over Scotland. He becomes not just a tyrant but a monster, one who slays the defenseless and the innocent. The witches play a role in Macbeth's destruction in that their prophecies awaken that which is in him: the fatal flaw in his own character.

How does Shakespeare portray Macbeth's flaw?

Macbeth's fatal flaw is that he is ambitious.  As with all tragic flaws, the flaw itself isn't necessarily a bad or evil characteristic.  That's what makes readers sympathetic to the hero character.  Macbeth is no different.  He dreams of improving his social status and gaining more power.  

Shakespeare alerts his readers/viewers to Macbeth's ambition early on when Macbeth is given the title of Thane of Cawdor.  That's good news to Macbeth, but then the flaw is exploited through temptation.  The witches tell Macbeth that he will be king.  

Now Macbeth has a problem.  He's been told he will be king and he's ambitious, which means he's not patient.  Add to that a wife who is equally ambitious and twice as ruthless and Macbeth starts down his slippery slope of murdering just about everybody.  

Despite his ambition and decision to kill Duncan, Shakespeare still allows the reader to see Macbeth as a flawed character instead of a sociopath.  Macbeth is hesitant to kill Duncan in the first place.  In fact he tells his wife that he won't do it, but she berates him and questions his manhood until he agrees again.  He feels super guilty after having killed Duncan too.  Shakespeare makes you really feel like it's always within Macbeth's power to put a stop to all of it, yet just can't quite do it (because of that flaw). 

What personality flaw in Macbeth accounts for his downfall?

The flaw in Macbeth's character that brings about his own destruction, both physical and spiritual, is that of rampant ambition. He desires political power above all else.

When he is tempted by the witches with the prophecy that he will become King of Scotland, Macbeth's latent ambition for power is evoked. He resists acting upon his ambition for a time. When he first hears the prophecy in Act I, Scene iii, Macbeth is tempted, but his reaction soon turns to one of passive acceptance: "If chance will have me King, why, / chance may crown me, / Without my stir." He does not maintain this philosophy for very long.

Influenced by Lady Macbeth's urging (and very effective psychological manipulation) in Act II, Macbeth soon murders King Duncan, as well as his grooms. Macbeth covers up the crime by blaming Duncan's sons, Malcom and Donalbain, and then goes to Scone to be crowned.

The prophecy has come true; he is King of Scotland. However, by murdering Duncan, Macbeth has fallen from grace. He knows that he has given his soul, his "eternal jewel," to the Devil himself. He soon falls from power, as well, through his continuing murderous acts.

Before the play reaches its tragic conclusion, Macbeth murders Banquo and Macduff's entire household. He becomes a monster through unfettered ambition: He equates being great with being powerful and views the crown of Scotland as "the ornament of life." All that remains for Macbeth is his own death.

What personality flaw in Macbeth accounts for his downfall?

I would add that Macbeth also was easily influenced, he was indecisive, weak of character, not sure of himself.    Clearly, it is Lady Macbeth's prodding that convinces Macbeth to go through with the murder of King Duncan.

After hearing the witches prophecy, he struggles with his conscience and decides that he will not kill the king.  However, after his manipulative wife gets through with him, he kills Duncan, I think against his own conscience, which immediately leads to the start of his mental breakdown. 

He is tormented after that and becomes even more susceptible to suggestion. He is frightened and insecure. He lashes out as his torment increases, which leads to more murders.

Macbeth does not really enjoy his time as king. As king he barely enjoys one celebratory dinner before it is interrupted by the ghost of Banquo. After that, he loses everything in his life that mattered, his friends, his wife, his peace of mind and his ability to sleep and eat.

What flaw(s) do you think account for Macbeth's fall?Macbeth brings down tragedy upon himself and his family. What flaw(s) do you think accounts for his fall?

The lack of self worth in Macbeth is certainly worth the time and effort of examination.  If he were more in tune with his place of honor and respect as an able warrior, a loyal thane to Duncan, and worthy family member and husband, he would not have succumbed to his wife's insistance that they murder the king.  We must admit that without her constant prattling about "are you a man?" he would not have acted on his impulses first planted by the witches' prophecy.  He would have waited...perhaps not patiently...for the honor to come to him in normal time--not catapulted himself to the head of the table before he was meant to be there.

What flaw(s) do you think account for Macbeth's fall?Macbeth brings down tragedy upon himself and his family. What flaw(s) do you think accounts for his fall?

I believe one of his deepest flaws is a lack of self worth. He was commended for his prowess on the battle fields-made the new Thane of Cawdor, but it was not enough. He obviously felt no pride at this, and only being the highest leader would make him happy. Something inside of him felt he was not good enough.

What flaw(s) do you think account for Macbeth's fall?Macbeth brings down tragedy upon himself and his family. What flaw(s) do you think accounts for his fall?

Macbeth's famous ambition certainly is his largest flaw, although in some ways his willingness to do whatever needed to be done probably helped make him a good soldier.

He also is superstitious, believing the witches' prophesies (probably because it is what he wanted to hear.) Although belief in witches was common in Shakespeare's time, if we look to the character of Banquo, we see that not everyone bought into it... or at least in Banquo's case there was a consideration of the source of the information. Remember, Banquo reminds Macbeth that the witches will lie to him to win him over - only in the end to "betray" him.

Macbeth is imaginative - which doesn't seem like it should be a flaw- but it DOES allow him to see and hear things that aren't there (the voice that says he has murdered sleep, the dagger, the dead Banquo).

What flaw(s) do you think account for Macbeth's fall?Macbeth brings down tragedy upon himself and his family. What flaw(s) do you think accounts for his fall?

The one that immediately comes to mind is a lust for power. The moment he hears the words Macbeth and King in the same sentence, his is consumed by his ambition. However, I suspect that other flaws that other contributors can mention are more interesting and less obvious...