I think people who troll to make others laugh is pretty nice of the user but I have recently been on chat and there was a "troll" (a failed one at that). It gets quite humerous when a kid thinks they can troll adults.
A couple of times I've tried posting off-topic stuff like ideas for TV shows; the "Good Cop/Bad Cop" one made it to the site while the one about wanting to do a live action remake of Wacky Races didn't.
I've trolled a few times, but I've done nice trolling, not trolling that hurts anybody but trolling that forces people to believe certain things about an anonymous person in order to bring up valuable opinions. Also helps me in psychological research (one of my enrichment studies in school)
Problem?