Why do I sometimes read disturbing stories?

Every once in a while, I find myself deliberately seeking out and attempting to read a story that deals in basic themes which I know ahead of time that I find unpleasant. It feels a bit like an entertaining game of chicken in which I try to see how long I can observe abysses before I have to bail out.

"I'm trying to see if I can find the mythical story in which good authorship can overcome a disliked subject matter!" crows the snooty part of my psyche.
"It's good to check up on things now and then to see if my tastes have changed." states the more rational part of my brain.
"Face the facts, kid. You're getting vicarious thrills out of literary grotesquerie and making up poor excuses for doing so!" says the odd part of my brain that addresses me in second-person.

I'm starting to believe that last guy more and more these days...