Almost everything Holden says indicates that he is alienated from those around him, particularly his constant denunciations of "phonies." Indeed, we see in the book's opening paragraphs that Holden is a bitter and angry young man:
If you really want to hear about it, the first thing you'll probably want to know is where I was born, and what my lousy childhood was like, and how my parents were occupied and all before they had me and all that David Copperfield kind of crap, but I don't feel like going into it, if you want to know the truth. . . . I'm not going to tell you my whole goddam autobiography or anything.
One example can be found in the book's opening chapter, when we discover Holden standing on a hill overlooking the football stadium, where Pencey Prep (his school, that he is about to leave after being expelled) is playing their rivals. As he puts it:
The game with Saxon Hall was supposed to be a very big deal around Pencey. It was the last game of the year, and you were supposed to commit suicide or something if old Pencey didn't win...You could hear them all yelling...on the Pencey side, because practically the whole school except me was there...
As his classmates attend the game, Holden stands by himself atop a hill, disdainful of his classmates, though we always feel he perhaps wants to fit in with them, even if he denies it.
Another example of alienation is when he finds himself at Ernie's, a bar in New York City. He is struck by how stupid and superficial everyone around him seems. "I was surrounded by jerks," he says. On the other hand, he reveals that everyone around him has a date with them:
I certainly began to feel like a prize horse's ass, though, sitting there all by myself. There wasn't anything to do except smoke and drink.
This is the same dynamic as earlier in the book: Holden expresses contempt for those around him, but seems to want their approval and, perhaps, their companionship.
J.D. Salinger, The Catcher in the Rye (New York: Bantam Books, 1965).