Unfriending

From time to time I've thought of "unfriending" certain people on Facebook and other similar sites. I'm sort of concerned about backlash, but I'm also tired of wasting time and energy reading posts from people who are consistently negative, bitter, judgmental, and so on. Also, I frankly have Facebook friends that I don't care about and who have nothing to offer me. So why bother? I think some selective unfriending is about to start. Has anyone else tried this and is so, how did it go? Discuss.