There's a memorable quote from one of Robert A. Heinlein's YA novels where the protagonist is told by a classmate that he's an idiot.

She responds to his excuse that his mistaken conclusions were logical:

`` Jack said slowly, "You used 'logic' again. What you call 'logic.' Rod, you use the stuff the way some people use dope. Why don't you use your head, instead?" Rod flushed... ''