Very stupid, especially the "trolls" who are racist, sexist, homophobic, etc.
You may think it's oh so hilarious to rile people up, but people have to deal with those things all the time in day to day life too. You're not being funny, you're just being an ******* and contributing to what they already go through. I'm glad I'm not such a pathetic person that I find enjoyment in harassing others.