Oh boy, this is one of my biggest things. I have lost so many friends because I simply don't call them or respond to them. I enjoy them, I like them just fine, but I have zero, ZERO interest in developing or nurturing a friendship with them. I primarily just want to be alone.
When I don't want to be alone, I'll go out shopping or I'll go to an art gallery reception or some other social thing by myself and I'll chat up the sales clerk or the people standing next to me, etc. But even then, I won't call up a friend and say, "Hey, wanna go to an art reception with me tonight?".
I have a big thing around any kind of obligation; I cannot stand making plans with people because then I feel an immediate sense of obligation. I don't want to be obligated to wait around for you to get ready and I don't want to have to leave when you get a headache and or get bored. I want to do what I want to do - end of story.
I sound like a five year old pouting child, but that's exactly how I feel.
So that's my understanding as to part of why I just want to be alone or do things alone.