There is a certain bit of psychological hacking going on calling connections "friends". Facebook has allowed a lot of people to reconnect and stay in contact, but maybe that isn't a good thing. Maybe we're supposed to only have transient interaction with most people. Maybe not knowing more about our cousins or our friend's friends is a sort of social lubricant. It's easier to be polite to my bigoted grandfather at Thanksgiving if I don't have daily reminders of his racism and homophobia. Perhaps the fact that none of the kids I grew up with are on Twitter is a feature of Twitter.
I could maybe get back on Facebook if I treated it like Twitter: I disconnect as soon as your stream turns to anything that even gives me the feeling of wanting to make a negative comment[0]. My twitter feed is full of a mix of on one hand very interesting people, and on the other very quiet people. I like it this way.
[0] I'm mostly successful at avoiding making that negative comment, which is kind of scary considering how many negative comments I do end up making.