If not for her reprehensible act of falsely accusing Tom Robinson--possibly the only person to ever act kindly towards her--Mayella Ewell would be an entirely sympathetic character in To Kill a Mockingbird. Mayella is one pitiful young woman: Nearly 20 years old, she acts as if she is a child, blubbering on the witness stand at the mere sight of "big bad Mr. Finch." Her behavior causes Judge Taylor to "scratch his thick white hair" and "let her cry for awhile" before admonishing her to behave like "a big girl and sit up straight." Mayella is forced to serve as the surrogate mother for the rest of the Ewell children (their mother is dead), and she rarely leaves the house. She has no friends, and doesn't even seem to understand the concept of friendship when she is questioned by Atticus. She "tempts" Tom Robinson--a married, crippled Negro man--simply because he is the most available male available, passing by her house daily and having acted kindly to her in the past. But her intentions on the day of the "attack" are not worthy of sympathy; instead, she calculatingly invites (orders) Tom into the house on the ruse of needing the hinges fixed on a door. When she gets her chance, she decides to kiss him, since
"... she never kissed a grown man before an' she might as well kiss a nigger. She says what her papa do to her don't count."
Tom's testimony brings up another point, that her father, Bob, may have been sexually abusing her--yet another reason to feel sorry for Mayella. But she decides to go along with Bob's story--that Tom beat and raped her when it must have been Bob who assaulted his own daughter--and her lies help to convict Tom and eventually cause his death.