In Harper Lee's To Kill a Mockingbird, Mayella Ewell takes the stand in Chapter 18. She is argumentative and confrontational.
When she is asked where she was "on the night in question," she notes that she was on the porch. When asked which one, she seems sarcastic, noting...
Ain't but one, the front porch.
She is an emotional wreck. After only one question, she is crying and nearly unable to speak. She quietly tells Mr. Gilmer that she is afraid—the source of her fear is Atticus.
"...What are you scared of?"
Mayella said something behind her hands. "What was that?" asked the judge.
"Him," she sobbed, pointing at Atticus.
She nodded vigorously, saying, "Don't want him doin' me like he done Papa, trying to make him out left-handed..."
She feels threatened by Atticus, even though he is amiable and calm. The source of her feelings may come from the fact that she has something to hide and is afraid that Atticus will be able to get it out of her. Mayella doesn't seem very smart, obviously, believing that identifying her father as a left-handed man is some kind of insult. The only way they are able to calm her is to speak to her like a child. The judge tells her he will "protect her," but that she is "a big girl, so you just sit up straight..."
Jem and Scout, much younger than Mayella, don't know what to make of her behavior, in that it is so unusual—defying explanation to their sharp young minds.
Mayella shows her father's disregard and prejudice toward blacks. During her account she recounts how she spoke to Tom—bossily—telling him to do some work for her. Then she becomes overwhelmed, frantic. Her testimony becomes fuzzy after, she alleges, Tom Robinson beat her.
Scout recounts that in the telling of her story...
...her recital had given her confidence, but it was not her father's brash kind: there was something stealthy about hers, like a steady-eyed cat with a twitchy tail.
(Cat are often associated with sneakiness.)
When Atticus begins to question her, she responds "resentfully."
She was looking at him furiously.
We can assume that Mayella is also not accustomed to anyone showing her any respect. She believes that Atticus is showing her disrespect as he speaks to her.
Won't answer a word you say as long as you keep mockin' me...Long's you keep on makin' fun o' me...Long's he keeps on callin' me ma'am an sayin' Miss Mayella. I don't hafta take his sass, I ain't called upon to take it.
We learn also that her life has not be easy. She has seven brothers and sisters, and she is the oldest; her mother has been dead a long time, and she only went to school a short while—she can only read and write a little.
Slowly...I began to see the pattern of Atticus' questions...Atticus was quietly building up before the jury a picture of the Ewells' home life. The jury learned the following things: their relief check was far from enough to feed the family, and there was strong suspicion that Papa drank it up anyway—he sometimes went off in the swamp for days and coming home sick.
They made their shoes from old tires. They collected water by hand from a nearby stream that came from the dump. The kids were always sick. The jury also discovers that she had no friends. This was a lonely young woman.
Her father is "tollable" (tolerable) to her. When Atticus asks if her father ever got violent with her when he was drunk, she denies it, but one already doubts this is true.
Mayella has a horrible life, sad life.