Friends? ...eh, never really there. My next older sister has always been the family socialite, and since I was always a grade or two ahead that was the age group that was around me; her friends were also 'my' friends. While I'm still in occasional contact with one person from that era, the rest of them have all vanished from my social sphere.
I always tended toward 'old' people, though. During church potlucks I would find a way to not sit at the tables with those of my age group. Instead, I would go sit with the 50-60 year-olds who were talking about things like different types of diabetes, which I frankly found much more interesting. Since I was quiet and well-behaved, they never seemed to mind.
Highschool years I spent largely without friends. There were a few that I'd hang out with, and we got along very well and still do when we see each other. However, as life has continued moving along, we don't see each other very often anymore. When we do it's always around many other people, and that eliminates the possibility of a good interaction while maximizing all my social inabilities.
So that leaves work. Again, I avoid social interaction as much as I can, but there is one person there who can tell I'm 'not quite right' and doesn't mind. He's kind of a misfit himself, and he knows that not being 'normal' (whatever that is) is okay. This friendship has survived for a few years now, I think sometimes more spite of me than not...