And I have one of those very loud, stupid laughs. I mean if I ever sat behind myself in a movie or something, I'd probably lean over and tell myself to please shut up.

The speaker’s self-description turns a small social habit—an unrestrained, “stupid” laugh—into a window on self-consciousness and alienation. The joke hinges on imagining oneself as an annoying stranger in a public space, suggesting a split between the self who acts and the self who judges. That internal heckler reflects insecurity and a fear of being perceived as crude or disruptive, even in moments of genuine amusement. The line also captures a defensive, comic candor: by mocking himself first, the speaker preempts others’ criticism. In Salinger’s fiction, this kind of self-lacerating humor often signals a narrator who is both perceptive and emotionally guarded.