What are the character traits in "Thank You, M'am"?

There are only two characters, Mrs. Luella Bates Washington Jones and Roger, in Langston Hughes’ short story “Thank You, M’am.” He uses both direct and indirect characterization to develop their personalities.

Hughes characterizes Mrs. Jones as a dignified, hard-working woman with a no nonsense attitude. Although she is a physically imposing person, her interactions with Roger exemplify her quiet, patient, compassionate nature. Mrs. Jones is walking home alone, late at night, from her job when Roger attempts to steal her pocketbook. Instead of screaming or calling the police, Mrs. Jones takes Roger home and teaches him a life lesson based on her own life experiences. After asking him a number of questions about his home life, she recognizes that Roger is a product of his Harlem environment. She teaches him to expect more from himself. She is kind enough to share her supper with him, but more importantly she shares her own experiences. She lets Roger know that she did some unacceptable things in her past. She cleverly allows Roger to make his own decisions about fleeing her apartment, which teaches Roger to trust in himself.

Roger is a young man who is growing up on the mean streets of Harlem, which greatly influences his character. He tells Mrs. Jones that no one is home at his house, which is why he is unfed and unkempt. Although he is bold enough to steal Mrs. Jones’ pocketbook, Roger demonstrates that he can be trustworthy during the short time he spends in Mrs. Jones’ apartment. He does not take her purse and run away, instead he stays and interacts respectfully with Mrs. Jones. Langston Hughes characterizes Roger as contrite and thankful at the end of the story when Mrs. Jones gives him money to purchase the shoes he wants.

Why doesn't Mrs. Jones ask Roger about his home or parents in "Thank You, M'am"?

Mrs. Jones does not ask Roger about his home life because doing so is superfluous; her powers of perception tell her all about Roger.

After Mrs. Jones foils Roger's attempt to steal her purse by muscling him to the ground with two or three passers-by noticing the physical conflict, Mrs. Jones asks if he will run if she frees him. When Roger replies that he will, she refuses to release him and examines him:

“Um-hum! And your face is dirty. I got a great mind to wash your face for you. Ain’t you got nobody home to tell you to wash your face?”
“No’m,” said the boy.
“Then it will get washed this evening,” said the large woman starting up the street, dragging the frightened boy behind her.

Further in the narrative after Mrs. Jones takes Roger home with her and asks if he is hungry, Roger reveals that there is no one at home where he lives. 

Her questions about his dirty face and if he is hungry added to Roger's revelation that his house is empty provide Mrs. Jones a wealth of information about Roger's home life. For, she can easily surmise from this information that his family is a broken one and Roger receives no supervision or loving care, both of which are extremely important. Her acts of Christian charity and love toward Roger make a profound impression upon him, and in his gratitude for her kindness in not reporting his crime "[T]he boy wanted to say something else other than “Thank you, m’am” to Mrs. Luella Bates Washington Jones...."

Why can't Roger thank Mrs. Jones in "Thank You, M'am"?

Your original question asked two questions and, according to enotes regulations, I have edited it down to one question. Please do not ask multiple questions.

To consider the question above, how do we respond to acts of random and unsought-for sacrificial kindness, as characterised by Mrs. Jones? One of the qualities that makes this story so powerful and memorable is that Mrs. Jones acts completely differently from how we would expect her to act. There aren't many people that would stop a thief and then take them home to share food with them, taking time to find out about their lives. It is surprise and shock that is expressed by Roger throughout the tale as he is dragged along and passively sits with Mrs. Jones, then said goodbye too before he is able to formulate a response or a way of saying thank you for such an unexpected act of kindness:

They boy wanted to say something other than "Thank you, m'am" to Mrs. Luella Bates Washington Jones, but although his lips moved, he couldn't even say that as he turned at the foot of the barren stoop and looked up at the large woman in the door. Then she shut the door.

It appears that, for some acts of kindness, there are no words to express how we feel and the gratitude that overwhelms us. The kindness of Mrs. Jones literally leaves Roger speechless, and he is not even able to stammer out the "Thank you" that he knows is insufficient.

Why can't Roger thank Mrs. Jones in "Thank You, M'am"?

In Langston Hughes's short story "Thank You, M'am," Roger is presented as a poor, hungry, and possibly neglected African American boy. He attempts to rob a woman named Mrs. Luella Bates Washington Jones in order to buy blue suede shoes. He's unsuccessful, however, and instead of taking him to the police, reprimanding him, or showing aggression, Mrs. Jones takes Roger to her home and tells him to wash his face and hands. She offers him food and shows him kindness, compassion, and generosity that he's never seen or experienced before; she even cuts him a piece of cake, teaches him a valuable lesson, and gives him ten dollars to buy the blue suede shoes.

Roger is shocked by this behavior; he's absolutely speechless and cannot believe what's happening. A woman of Mrs. Jones's social status is willing to treat him kindly and like a normal human being. Before he even gets the chance to say a proper "thank you" to Mrs. Jones and express his gratitude for everything that she's done for him that day (including leaving her purse in his presence, which suggests that she trusts him), Mrs. Jones sends him on his way, and he never sees her again. Despite not being able to say "thank you," Hughes reveals that Roger will never forget Mrs. Jones's kindness.

Why can't Roger express his feelings to Mrs. Jones at the end of "Thank You, M'am"?

In Thank You M'am by Langston Hughes, Mrs. Luella Bates Washington Jones could so easily hand Roger over to the police after he tries to steal her purse. Instead, she recognizes a need in him for some wise, adult intervention because his actions reveal a misdirected boy in need of guidance. She spontaneously decides that she can not only teach him a lesson but also show Roger that he does have other choices in life and petty crime will not serve him well. Mrs. Jones relates to Roger and remembers a time when she "wanted things I could not get." She is not a wealthy woman and she tries to show Roger that there are other ways to get what you want, even suggesting that he could have asked her, which has Roger bemused. Her actions do reveal to him that not everyone mistrusts others and that everyone deserves a second chance.

At first, Roger worries that Mrs. Jones is going to take him to the police, and even after she takes him into her home, he considers running away but something stops him. He does not expect her to trust him and when she does, he feels a need to offer some token of gratitude by offering to go to the shop for her. The last thing he expects is that Mrs. Jones will give him a decent meal and even give him enough money for the shoes. 

Mrs. Jones's actions have such an impact on Roger that he knows that he owes her far more than a simple thank you but he is overwhelmed by her generosity and by the fact that she wants nothing in return except that he should "behave yourself." There is potential to interpret a double meaning from Langston Hughes's use of the word large as Mrs. Jones's "large" personality and compassion, for Roger, have  had a big influence (hopefully) on his life and his future, rendering him almost speechless. 

Why is Roger afraid in "Thank You, M'am"?

When Roger attempts to steal Mrs. Luella Bates Washington Jones's pocketbook, he trips, and Mrs. Jones quickly grabs him by the collar. As soon as Mrs. Jones grabs him by the collar and refuses to let go, Roger attempts to escape and becomes frightened that she will punish him for his attempted robbery. Roger believes that Mrs. Jones will either physically punish him or report him to the authorities. Mrs. Jones proceeds to drag Roger back to her home before she lets go of him and asks him several questions about his background and motivation to steal her pocketbook.

Immediately after Mrs. Jones lets go of Roger, he asks her if she is going to turn him into the police. As a young black male, Roger understands that the law is not on his side and fears being arrested. Ironically, Mrs. Jones does not punish or lecture Roger about his behavior and proceeds to make him a hot meal before giving him ten dollars to buy blue suede shoes. Mrs. Jones's benevolence and hospitality have a significant impact on Roger, who is astonished and appreciative of her generosity and forgiveness.

Why can't Roger say "thank you" to Mrs. Jones as he leaves?

"Thank You, M'am," by Langston Hughes, follows the story of a young boy named Roger who attempts to steal a purse from a woman, Mrs. Luella Bates Washington Jones.  The first paragraph explains their encounter:

"She was a large woman with a large purse that had everything in it but hammer and nails. It had a long strap, and she carried it slung across her shoulder. It was about eleven o’clock at night, and she was walking alone, when a boy ran up behind her and tried to snatch her purse. The strap broke with the single tug the boy gave it from behind. But the boy’s weight and the weight of the purse combined caused him to lose his balance so, instead of taking off full blast as he had hoped, the boy fell on his back on the sidewalk, and his legs flew up. the large woman simply turned around and kicked him right square in his blue-jeaned sitter. Then she reached down, picked the boy up by his shirt front, and shook him until his teeth rattled."

Here readers are introduced to Mrs. Jones's great strength. She was not about to let a young boy take her purse without a fight. Instead, she invites him into her home and talks to him about life. She instructs him to wash his face, with warm water and a clean towel, and offers him food. She assumes he must be hungry if he is trying to steal from people. Instead, he tells her his real purpose: he wanted to buy blue suede shoes, a mark of fashion in his time period. Rather than reprimanding him or threatening him, she tells him he could have asked:

"'Well, you didn’t have to snatch my pocketbook to get some suede shoes,' said Mrs. Luella Bates Washington Jones. 'You could of asked me.'"

Roger is surprised by her calm and gracious response. How often does someone try to steal from someone and then get treated kindly? He wasn't expecting her hospitality or kindness. In fact, he asks her if she is going to take him to jail, which is probably what he believes he deserves for his crime. 

At the end of the story, we see that Roger struggles to say thank you to Mrs. Jones for her kindness:

"The boy wanted to say something else other than 'Thank you, m’am' to Mrs. Luella Bates Washington Jones, but he couldn’t do so as he turned at the barren stoop and looked back at the large woman in the door. He barely managed to say 'Thank you' before she shut the door. And he never saw her again."

It's likely that he didn't feel that the words thank you were enough; it was too simple a response to such extraordinary kindness. Or, perhaps he was still in shock. Maybe he truly could not understand her behavior and was trying to make sense of what had happened. Whatever the case, he isn't able to find the right words as he says goodbye to this mysterious woman who showed him such unbelievable grace and kindness after he tried to steal from her. 

In "Thank You, M'am," what is a character trait of one main character?

"Thank you, M'am" is an incredible story by Langston Hughes exemplifying the Harlem Renaissance.  If you need to take a look at only one set of character traits, you only have two to choose from:  Mrs. Jones and Roger.  These are the only two characters in the story.  I consider Mrs. Jones to be the main character, so that is the character I will focus on in answer to your question.

Mrs. Jones full name is Mrs. Luella Bates Washington Jones.  Her behaviors certainly show what kind of person she is:  full of dignity and pride, always expecting the full potential out of other people she meets.  Roger is one of those people from which she expects full potential.  Ironically, Mrs. Jones meets Roger as he attempts to steal her purse.  Always a non-judgmental person, Mrs. Jones adopts Roger as a kind of moral mentor, showing her compassion and kindness to others as a result.  Mrs. Jones is a perfect candidate for compassion towards Roger.  She has been through rough times when she "wanted things I could not get."

[I had]done things, too, which I would not tell you, son—neither tell God, if he didn’t already know.

Sharing a rough past is a perfect way for Mrs. Jones to connect to Roger.  She shares both her humility and her morality and her faith with Roger.  Through these things, she convinces Roger not to steal, especially for something as silly as shoes.  Mrs. Jones not only gives Roger the money to buy the shoes, but also shares her meager food with him. A true role model, Mrs. Jones proves herself to be both honest and sincere.

Why does Mrs. Jones close the door before Roger can say "thank you" in "Thank You, M'am"?

Mrs. Jones closes the door on Roger because she is does not want to seem sentimental.  She also wants to get rid of him as quickly as possible because he has reminded her of some unpleasant parts of her own past.

Mrs. Jones is an older woman who stops Roger from trying to steal her purse.  Instead of turning him in to the police, she takes him home and has him wash up, then cooks him dinner.  At first he is surprised, but then he comes to appreciate her.  She tells him she has done some bad things in her life too.

"I have done things, too, which I would not tell you, son—neither tell God, if he didn’t already know.” (p. 3)

The boy’s attitude completely changes under Mrs. Jones’s tutelage.  He becomes respectful and trustworthy.  He even offers to go to the store for her.  After she cooks him dinner, she gives him the money for the schools he wanted to buy—the reason he tried to steal her purse.  She tells him not to try to steal from anyone else.

[Shoes] come by devilish like that will burn your feet. I got to get my rest now. But I wish you would behave yourself, son, from here on in. (p. 4)

When she closes the door before he says thank you, she has reached her limit.  She did care about the boy, and saw him as a lost soul.  She wanted to teach him a quick lesson, because perhaps no one did for her, but then get rid of him as soon as possible so she would not have to think about her past.

What are the boy's character traits in "Thank You, M'am"?

In Langston Hughes's celebrated short story "Thank You, Ma'am," Roger is depicted as a misguided, sensitive adolescent who regrets attempting to steal Mrs. Jones's purse. When Roger initially attempts to steal Mrs. Jones's purse, he falls to the ground and she immediately grabs him by the collar. As Mrs. Jones proceeds to drag Roger home, he demonstrates honesty by admitting that he will try to run away if she lets him go and reveals his sensitive side by apologizing for his actions. Roger is also a frightened, timid boy who fears that Mrs. Jones will take him to the authorities.

Once Roger arrives at Mrs. Jones's home, he contemplates running out the door but decides to stay and wash his face before he enjoys a home-cooked meal. Roger has faith that Mrs. Jones is a hospitable woman and proves that he was simply a misguided child by attempting to earn her trust. Roger even makes sure to sit far away from Mrs. Jones’s purse to ease any suspicions.

Roger then displays his manners by offering to get milk for their meal and is surprised when Mrs. Jones gives him ten dollars to purchase a pair of blue suede shoes. Roger is extremely grateful for Mrs. Jones's hospitality and struggles to express his feelings. Roger is at a loss for words and simply tells Mrs. Jones, "Thank you, m’am" before she shuts the door.

Overall, Roger is a sensitive, desperate boy, who has a good heart and is in need of guidance and compassion.