I agree that fb completely sucks. I've never had an account but know how it works through my wife, family and friends.
Beside the fact that it was created by a total d bag and that it is completely Orwellian, fb causes tremendous social anxiety and depression. People determined to show how many friends they have and how great their life is.
Women are particularly vulnerable as they see that ugly girl from school now look beautiful and engaged to a hunk. Or they see Sarah lose 50lbs and get a bikini body.
Before fb, people's envy was confined to their social circle in real terms ie to people they actually saw. Now it's global and they find themselves jealous of someone they barely knew on that work placement they did in Paris back in 2012.
The fb machine will implode within the next decade as kids now don't dig it since mom and dad use it.
Get out into the real world and actually meet people and realise that friends come and go but the really great ones stay and for them, you don't need fb.