Everyone else in the book (except Nelson, Rebecca June, and Mrs. Smith).
Really. As soon as Rabbit gets involved with people, problems occur. The further outside of society he gets, the happier his life becomes. His father says he became Rabbit's "enemy" when Rabbit left Janice. Eccles antagonizes him by instead of helping Rabbit explore his options, telling him that he must go back to Janice, at all costs. Janice antagonizes him, just by not being compatible with him – and by killing his kid. Yet, he keeps voluntarily and involuntarily involving himself with people. Even Ruth says he’s "not enough to stink," and then threatens to abort his baby if he doesn’t marry her. Sorry, but that’s antagonistic. Rabbit’s struggle is learning to live among people without being antagonized by them. At the end of the book he probably still hasn’t, and that’s why he runs.
Harry "Rabbit" Angstrom
Rabbit antagonizes himself, too, big time. He is paranoid most of the time, and feels trapped almost everywhere he is. His ambition for a life that doesn’t feel like a trap antagonizes him constantly. His attempts to conform the reality to his fantasy (like when he thinks he can have sex with Janice even though her body has not recovered from childbirth) antagonize both himself and those around him.