I struggle with an eating disorder and depression, so Facebook was absolutely the worst place to be spending time. Every time I'd log in, I'd end up comparing myself with others...ie. who looked thinner, who had more 'friends,' which statuses got 'liked' the most, and so on. I just ended up feeling crummy about myself. I've since deactivated the account and feel a whole lot better. People are really surprised when they find out I'm not on Facebook, but I figure that this way, I find out who my true friends are.