In The Catcher in the Rye, what do Holden and Stradlater fight over?
Holden and Stradlater fight because Stradlater has had a date with Jane Gallagher. Holden knows Jane and feels sorry for her because her parents were divorced and her stepfather walked around her house naked. He knows and understands Jane as a person and he feels like Stradlater is only trying to take advantage of Jane and doesn't really appreciate her.
They also fight because Stradlater acts entitled and asks Holden to write his English composition while Stradlater is on the date with Jane. He tells Holden not to put the commas in the right places so it appears as though Stradlater has written the composition. Stradlater is the kind of athletic, handsome boy who has things easy and who plays by the rules to the degree that he can stay at school. Holden annoys Stradlater by writing the composition about a baseball glove rather than about a room or house, as Stradlater had asked him. Holden then tears up the composition in anger, and they get into a fight.
The fight concerns the fact that Stradlater has gone on a date with Jane Gallagher. Holden starts to question Stradlater about what occurred on the date and he talks himself into a fury, imagining that Stradlater made sexual advances toward Jane, and possibly Jane responded to him. Holden can't stand the fact that Stradlater actually went out with Jane, because he does not have the courage to ask her out himself. He longs for Jane silently, keeping his feelings to himself.
Stradlater is dismissive of Holden's questions and this only serves to anger him further, until Holden can't help but hit Stradlater. He tells him that Jane is not the kind of girl that he should go parking with. She "Keeps her kings in the back row" a metaphor for her sexual purity.
Holden and Stradlater fight over Jane Gallagher's date with Stradlater. When Stradlater comes back from his date, Holden had already spent the majority of his time wondering what they were doing and if stradlater was taking advantage of Jane. When Stradlater came back and wouldn't offer much information to Holden, Holden lost it and started punching him due to his overflowing emotions.