If I know the person I'm usually quite happy to add them, there are very few people who I dislike strongly. I've reduced the number of people I've added, mostly because I'd talk with someone at a party or two and now I have a bunch of friends I don't really know/will likely never see again. I tend not to unfriend though, usually I'll just hide posts from those I'm not interested in. I've noticed being unfriended a couple of times but they've all been people I haven't seen for a while and I look at their profiles/whatever so infrequently I don't actually know when they did it. Can someone explain why they keep their friends within a set number? That seems like a strange practice to me, the amount if people you want to interact with will vary over time.