I self-sabotage (potential) friendships like that too, although my reasons are different. I tend to have different sets of friends, some of who I'll see sometimes when I'm depressed, others who I want to spend my time with when I'm up. If I'm depressed for a long time... I tend to withdraw, and the people who would normally always be out with me doing things will eventually stop trying to invite me out. And when I come out of it, I'll be too embarassed to contact them again. When I'm in an up phase I tend to neglect my calmer friends because I don't want to annoy them... but then I withdraw from them and the same thing will happen! But my up times don't last more than a few weeks so I tend to be able to recover those ones.