Why did the author end the book with the line "Most people are (nice), Scout, when you finally see them." To whom or what is Atticus referring? What does he mean when he says "...when you finally see them"?
This line spoken by Atticus is a restatement of his attitude about all people. He feels that one should really get to know people first before judging them. Then, once someone gets to know and understand another, there is usually no conflict between them; they are nice.
In Chapter 3 Atticus listens as Scout relates the events of her first day of school that have upset her; when she begs him to let her stay home, Atticus replies that she first needs to learn a simple trick, she will be able to get along with almost everyone. He instructs Scout,
"You never really understand a person until you consider things from his point of view...until you climb into his skin and walk around in it."
Throughout the course of the narrative, Atticus has practiced this "climbing into [another's] skin" and has led his children to understand, after they have gotten to know her, that Mrs. Dubose was not really the horrible woman that Jem and Scout thought she was, Mr. Cunningham also has some sympathy, and Mr. Ewell was so hateful because in the court room Atticus destroyed Bob's credibility and threatened whatever pride he may have had left. Seeing Boo Radley and talking with him has led Scout to believe that Boo is all right, after all.