In To Kill a Mockingbird, an important theme is that of conflict between different races. The people of Maycomb are racist and close-minded, and they dislike the idea of white people having personal relations with black people. In this context, Mayella did something unforgivable: she was attracted to and kissed a black man. She is ashamed and feels an enormous guilt for her actions. This guilt leads her to falsely accuse Tom Robinson as opposed to admitting her wrongdoing.
