In his A Treatise of Melancholy, written in 1522, Timothy Bright touches on what makes Hamlet procrastinate: melancholy.
Touching actions which rise from the brain, melancholy causeth dullness of conceit [apprehension], both by reason the substance of the brain in such persons is more gross, and their spirit not so prompt and subtle as is requisite for ready understanding.
This melancholic temperament of Hamlet causes him to feel a deep repulsion for his mother's act of remarrying, as well as the hopelessness of any efforts to improve the corrupt court of Denmark. His melancholic nature also effects his interminably long deliberations born of doubt and distrust which are evidenced in his soliloquys. Bright further explains Hamlet's fear of being accused of regicide,
Such persons are doubtful, suspicious, and thereby long in deliberation, because those domestical fears, or that internal obscurity, causeth an opinion of danger in outward affairs where there is no cause of doubt. Their dreams are fearful, partly by reason of their fancy, waking, is most occupied about fears and terrors, ...and partly through black and dark fumes of melancholy rising up to the brain....
Another reason that Hamlet procrastinates is simply this: Had Hamlet gone naturally to work as the brave youth that he is represented to be, there would have been an end to the play. Shakespeare had to delay Hamlet's revenge in order to have a worthy drama.
This question is THE question of the play, and there are lots of theories. Here are a few:
1. Hamlet over thinks taking action and ends up talking himself out of it. He becomes caught up in the details and potential consquences. He specially comments on this phenomenon in the Act 3 soliloquy.
2. Hamlet is very concerned with morality (look at how he feels about his mother's behavior and his own thoughts of his afterlife). He is afraid to kill Claudius because he feels he could be damning his own soul.
3. He wants to kill Claudius when there is no chance Claudius would go anywhere but Hell. When Hamlet sees him in the act of praying, he worries that Claudius would have a clean soul and therefore not suffer in his afterlife.
4. It just isn't in his nature -- he is a "lover not a figher" more inclined to hang out with a groups of actors in the theatre than to learn the art of warfare and prove himself on a battlefield, therefore he isn't up to the task, certainly not like Fortinbras, whom he admires in the middle of Act 4.
5. He is very depressed -- maybe he is just too depressed to act and thinks all his actions are rather worthless. He seems to touch on this theme in the soliloquy at the end of act 2.
There is not one right answer here-- you have to reveiw the play and decide for yourself. Which option(s) stand out to you? Which would you be able to best defend with EVIDENCE from the TEXT which is at the heart of any literary analysis.
There are several factors to consider in order to understand Hamlet's actions or his inaction.
First, the play takes place in a Catholic world. Both murder and suicide are mortal sins. Hamlet's dilemma is how to accomplish his goal, avenging his father's murder, and not lose his soul.
Since Hamlet is over thirty and still attending university, it would appear that he prefers the academic world over the world of the court. He is a thinker. It would appear that he likes to examine something from every possible angle before he commits himself to an action.
He is told about the murder from a ghost that looks and sounds like his father but is he? How does he know that the ghost is really his father and not the devil tempting him into an action that would cause him to lose his soul? Until he is certain, he must wait and see. Claudius's reaction at the play confirms the ghost's story.
From this point in the play, Hamlet must find a way of achieving his goal, the death of Claudius, and manage to keep his own soul.
There are numerous reasons for his procrastination. An even more important question becomes, does he achieve his objective and still retain his soul? Do flights of angels attend him?
I'm not sure I would call it procrastination; instead, I would call it hesitation. Procrastination generally happens when we don't want to do something (such as cleaning the bathroom, pulling weeds, paying bills, or whatever task you might find unpleasant). Hamlet clearly wants to do something even before he discovers his "gut" instinct is true--that Claudius killed his father. Once he's reasonably sure about that, he is resolved. His hesitancy, it seems, is moral. Hamlet is not a man who would kill easily and without cause, yet we know he is resolved because he inadvertently kills Polonius thinking it's Claudius. Hamlet is a moral man who understands the consequences of murder; thus, he is hesitant to commit the act easily.
Why do we all procrastinate? This question is asked of most of the characters in the play and the play offers some answers. Procrastination though is a derogatory view at least with regard to Hamlet. It suggests that Hamlet delays that which should be done. I think the play establishes that revenge is a wrongful act and not only should it be delayed, it should be dismissed.
Hamlet's discovers that the biggest problem with revenge is the hot blood/cool reason ("blood and judgment") dichotomy. He is unable to "summon up the blood" and "then imitate the action of the tiger", to take a quote from Henry V. Revenge is a bestial act committed by the likes of Pyrrhus, the Hyrcanian beast. Hamlet sees in the the Player King's first speech as he laments in the following soliloquy that he just can't command his body to act the avenger however he may be prompted to do so.
It's Hamlet's ability to reason that keeps him from killing Claudius at one of the prime opportunities in the play. And yet it is Hamlet's "rash and bloody deed" that leads to Polonius' death.
This and the broader question of "procrastination" that Hamlet's predicament prompts is explored by the Player King in "The Mousetrap", by Hamlet in his 2B soliloquy and by Claudius as he plots Hamlet's demise with Laertes.
Then ask why Hamlet, Claudius, Laertes, Prince Fortinbras, Pyrrhus, and even Osric, Lucianus and the gravediggers delay their duties.
see generally, Harold Jenkin's Arden Hamlet