In the eyes of Jem and Scout, Atticus seems to be a disappointment because he does not do the things other kids' fathers do. In the first place, he is old, "nearly fifty", while their friends' fathers are in their thirties. Because of his age and his temperament, Atticus does not do things like play football, prefering instead to "sit in the livingroom and read".
There is nothing Atticus does that would impress Scout's and Jem's friends. He "works in an office, not in a drugstore...(does) not drive a dump-truck for the county...(is) not the sheriff...(does) not farm, work in a garage, or do anything that could possibly arouse the admiration of anyone". Worse yet, he wears glasses, and does not "do the things (their) schoolmates' fathers (do)...he never (goes) hunting...(does) not play poker or fish or drink or smoke".
Jem is embarrassed when Atticus refuses to "go out for the Methodists" in a fund-raising football match against the Baptists, saying he is "too old for that sort of thing" Jem, Scout, and Atticus have to watch from the sidelines as braggy Cecil Jacobs's father makes a touchdown for the Baptists. Miss Maudie points out to Scout that her father "can make somebody's will so airtight can't anybody meddle with it", and that he is "the best checker-player in this town...(and) he can play a Jew's Harp". These "modest accomplishments" are not what she is looking for, however, and they in fact "make (Scout) even more ashamed of (Atticus)" (Chapter 10).