I can relate. I don't mean to be mean or unkind but when I see almost anyone I know someplace where I have my mind set that I'm there to get in, get what I need, and get out. I try to veer away from them. They will have to be a very good friend for me to want to sidestep my plans to talk with them. I too, think that I'm built in a rather anti-social way.
After my first wife and I broke up, I had to give it a real effort to go out and socialize. I really didn't like it at first. I seriously didn't know how to talk to people, to make interesting conversation, or how to act around women. I had to hang out with a group of guys for awhile to get back into the swing of being social. I did get into a routine and then it wasn't so bad. Option 1) Go to work, come home, fix myself dinner, and work out, or option 2) go out to the bars and meet up with some aquantances and meet some women. During that stint I met the person who became my new wife. And I thought, whew, that's over. Now I don't have to go out so much.
But she's a good thing for me, she makes sure that I answer my cell phone when it rings because if she's not there and I hear it ring, I won't answer it 75% of the time. She's also there to make sure that I keep up with my friends. And I really do love her for it, because when I'm out with my friends I really do enjoy myself. But I think I'm the weird kind of person that would have no trouble travelling the world alone, not having any friends except for my dogs, and being pretty much a loner in the world. Luckily I have my wife to make sure that I don't become a hermit. I've just never gotten that lonely feeling that people say they get when they aren't around friends and loved ones. I guess I do a fairly good job entertaining myself.