Atticus is becoming stressed out about the trial because he is about to embark on the difficult task of defending a black man in front of a predominantly prejudiced community. Atticus knows that he will lose the case, but has to display courage in the face of adversity. Atticus is aware that his defense of Tom Robinson opens his family to criticism and possible danger throughout the community. His sister, Alexandra, has become somewhat annoying with her constant criticism and disapproval of Atticus' choice to defend Tom. Following the mob scene, Scout notices the "subtle change" in Atticus' behavior. Perhaps Atticus is becoming less patient with the racist comments and attitudes throughout Maycomb's community. Atticus is under a lot of pressure and feels that he needs to maintain his integrity by defending Tom. It is not easy choosing to defend an African American in 1930s Alabama, and Atticus is beginning to show signs of fatigue and stress leading up the trial.