Personally, I don't mind trolls, I occasionally indulge in trolling, and I can see why they do it. The fun you get from watching someone get steadily more angry as you screw around with them is hard to convey. That said, I do have my limits, and the limits to which I find other people trolling funny. In general, I don't mind as long as it's vaguely clever and not just saying the opposite of what their victim is saying or seriously mentally injuring the victim.
What do you think about trolls and how often/do you troll?
What do you think about trolls and how often/do you troll?