I have people on my friends list that I don't like, but they are family by marriage. If I would un-friend them bad things would happen & that's something I don't want to happen. It's amazing that I know 455 people personally out of the 460 people that are on my friend's list. The other five people that I have on my friend's list are journalists that I follow on both Facebook & Twitter. I don't understand when people add people as friends that they don't even know. To me that seems a little bit dangerous since if they turn out to be crazy they have access to your wall & can write a whole bunch of messed up stuff on there before you even know it. Afterwords, you have to do damage control by deleting their postings & such.
I have a LOT of facebook connections that are just that, people I knew from high school that I can keep in touch with, but they aren't really friends in the hang out kind of way.
There are a few people I have on facebook who I've never actually met, but who I've known online for years. I tend to refuse friend requests unless I know who sent them. Even if I've got 12 mutual friends with someone, if I can't remember meeting them, they don't get added. Though funny thing, someone once added me who I had 3 mutual friends with, but one was a freind from my home town, one was a friend from my school (which was in a different city), and one was a relative who lives in Scotland. It was weird, they all knew this other person who as a result added me.
There are also a couple of people I never really hung out with, but nobody I dislike. Then again, there aren't that many people I dislike, and the only person I really don't like who comes to mind (one of my tutors), wouldn't add me on facebook anyway. Though I did see her in the gym the other day. That was weird.