I used to not value sandbox friends, or perhaps, think of myself as not having any though that wasn't strictly true. One of the strange (in a good way!) things about the life I've developed these days is it involves LOTS AND LOTS of sandbox friends (and things like LJ help with maintenance of those connections). But I always get to feeling unbalanced/deficient when I spend my time nearly exclusively with sandbox...because at the end of the day, I really need the close, lasting friendships in order to feel socially fulfilled. (On the other hand, the sandbox is the only place I've ever managed to make lasting friends. And I do love sandboxes.)