It's like this: the Internet is for connecting with new people, not people you could just call on the damn telephone. That and of course porn, neither of which should ever reveal your true identity to anyone but a merchant selling you something (usually porn). Facebook drags reality into the Internet, bringing with it everything I hate about real life without any of the interesting stuff. I, personally, come to the Internet to avoid real life, just like I play video games to do things I couldn't physically do. Facebook, however, emphasizes real life rather than creating any kind of other world.
Oh, and everyone I know who does a lot of Facebook is a mega-douche. I look around me in the computer center at school, and all the douchebags are on Facebook, hogging computers with conversations they could have on the telephone.