How does Mrs. Dubois irritate the children as they pass her house on Saturday? What comment finally pushes Jem over the edge and causes him to forget his father’s commands regarding Mrs. Dubose?

The day after Jem's twelfth birthday, he and Scout go to town to spend some of his birthday money. On the way, Mrs. Dubose yells to Jem that he broke Miss Maudie's grape arbor that morning, which is untrue, and yells at Scout for wearing overalls. Then she starts yelling at them about how Atticus is defending "niggers," and says that Atticus is no better than "the trash he works for." Jem tries to follow Atticus's advice regarding Mrs. Dubose: just hold your head high and be a gentleman.