I closed my fb account just about a year ago. I don't miss it at all.
Too many people posting nonsense about the most mundane aspects of their lives. Not to mention, I don't really want people knowing my business so I wasn't crazy about the complete lack of privacy, regardless of what you had your privacy settings at.
I feel the same way about Twitter too. I don't care enough to follow anyone and don't want anyone following me.
Btw, I'm really not at all anti-social. I just prefer to have actual conversations with people.