[Z]

I don't care, because I regularly de-friend people. For me anyway, it's never done in a personal, spiteful way, it's more because I'm very paranoid about my online privacy and if I notice my friend count is creeping way up, I'll prune it back down again. At the moment I'm on around 250-260 people I think, it's an alright number, I'll probably delete more people again in the new year.

My general rules of thumb are:
1) would I stop to talk to them in the street and tell them anything about my life? If no, why are they on my Facebook where they can find out that kind of information anyway?
2) have I seen them in, say, the last year? If not, do I plan to see them when we can next conveniently do so? If not, bye bye.
3) are they massively irritating on Facebook? If yes, bye bye.