As a kid I read a story, I think by Bruce Coville, wherein the protagonist discovers the ability to ... Er, I don't quite recall. I think he manages to "slip into the folds of the universe" or something like that. Whatever he manages, it gives him a full understanding of how everything works.

The end result is that he loses all joy because there's no wonder left in the world for him. I think the closing scene in the story is him wandering into carnival machinery, being told by staff that it'll ruin the surprise, and him saying he doesn't care because he already understands the machinations.