Why did Scout begin to cry in front of Atticus?

Aunt Alexandra wants the children to know all about the Finch family and uphold its genteel heritage, but Atticus has not introduced them to the entirety of their family history, and instead has told them amusing stories, such as how their cousin Josh went insane at university. Aunt Alexandra tries to pressure Atticus into telling the children why they should behave and "live up to your name." Atticus makes an attempt, but when Scout begins to cry over this strange side of her father she has never seen before, he returns to his original principles and finds himself incapable of passing on what Aunt Alexandra deems important. Scout is relieved when her father returns to the same old Atticus, and says she knew what he was trying to do, but that "it takes a woman to do that kind of work."