Growing up in a Jewish-American household where the parents demanded high achievement, Juster was intimately familiar with expectations, though in his case many of his parents' hopes were centered on his older brother, an academic star. The Terrible Trivium, the well-dressed, polite demon who sets the questers to mindless tasks, was Juster's way of representing his own tendency to avoid what he should be doing in favor of a more congenial occupation, such as his evasion of the grant project to write "The Phantom Tollbooth". Juster drew on Feiffer's life experiences as well; the Whether Man's adage "Expect everything, I always say, and the unexpected never happens" was a favorite of the cartoonist's mother.