In The Catcher in the Rye what does Holden mean by that kills me?

Holden uses the phrase “that kills me” to express strong dislike toward something. However, Holden is complex, filled with contradictions, not to be taken at face value and is given to exaggeration for effect on both himself and the listener/reader. The phrase also indicates a loss of innocence of childhood: as he says of adults who use profanity: “when you’re around them…you have to be on your guard—that is, if you want to be mature” (Salinger 32).

He uses hyperbole, understatement, vulgarity, lies or changes his account according to who his current listeners/readers are in the complex psychological process of coming to terms with adult hypocrisy and life itself.