The obvious reason Holden leaves Pencey is that he’s flunking out. Not only has he failed all of his classes except for English, but he’s also just come back from New York, where his fencing team had to forfeit their matches because he lost their equipment on the subway. Seeing no reason to stay on campus and wallow in humiliation, he simply leaves. But Holden’s motivation for running away also stems from other frustrations having to do with the culture of Pencey. All of Pencey’s pupils come from wealthy families, and Holden finds the atmosphere of his school stifling. He expresses this sentiment in the first chapter: “The more expensive a school is, the more crooks it has.” Whether or not Holden’s perceptions of his peers are accurate, he clearly feels unable to connect with them. He therefore runs away from Pencey because it represents a place of profound loneliness.