Mayella was afraid of Atticus in the courtroom because he was treating her with respect and she had never been treated like that before. She was also afraid of Atticus because he might ask her questions and she might give him answers that could lead him to the truth and then her father would do horrible things to her.
The judge asks Mayella what she's scared of, and she points to Atticus
Actually, Atticus doesnt mock Mayella. Mayella thinks Atticus is mocking her because he is caller her Ma'am and Miss Mayella, which she isnt used to.
Atticus believed that Mayella falsely accused Tom Robinson of a crime because she was afraid of the consequences of her actions. He thought that Mayella was pressured by the expectations and assumptions of the society she lived in, which led her to blame an innocent man rather than face the truth about her own mistakes.
Mayella Ewell was surprised and taken aback by Atticus's politeness during the trial. She had likely never encountered someone treating her with respect and courtesy before, which made her uncomfortable and defensive.
Mayella cries because she thinks Atticus will find out that her father really did it.
Atticus says he only has one witness left to call after Mayella Ewell has finished testifying. This witness turns out to be Tom Robinson, whose testimony is crucial for the trial.
Bob Ewell, who is Mayella's father, beat her up
"Tempting a Negro"
Bob Ewell or Mayella
Mayella's reaction to Atticus' behavior in court is ironic because Atticus is the only person actually trying to defend her and seek justice for her, yet she is hostile towards him. Despite his efforts to help her, Mayella feels threatened by Atticus' questioning and sees him as an enemy due to her prejudiced views.
Atticus aims to show that Mayella is not a reliable witness by poking holes in her story and highlighting inconsistencies. He tries to establish that Mayella's accusations against Tom Robinson are a result of her own personal issues and not based on factual events. Atticus demonstrates that her testimony lacks credibility, bringing into question the integrity of the case against Tom.
When Mayella is on the stand the question Atticus asks that makes her furious is "How?" She has just described how Tom Robinson choked and beat her, and Atticus asks Tom to stand up. This draws the jury's attention to the fact that Tom's left arm is useless, making it highly unlikely he was Mayella's attacker. When Tom stands, Atticus asks Mayella if Tom is the man who attacked. When she responds that he is, Atticus asks, "How?"