I am perfectly happy being alone for long periods of time. While I'm not anti-social by any means I an very comfortable not being around people. For many years my work life consisted of me leaving home every week (either Sunday night or Monday morning) and not returning home until Friday. On business trips I would spend time with people all day. Every night I ate at some resturant or another alone. I would take a book or newspaper with me to read. Aftet dinner I would go to my hotel room, lock the door & close the blinds. From that point on I was in "my cave" until the next morning. While traveling it would be highly unusual for me to have a conversation with a seat-partner on an airplane or even with others at the airport.
My wife used to constantly ask me how I could stand being alone in various cities all over the world. She just couldn't (and still can't) understand my need for quiet time.
If I am home alone I usually have many projects going on or just enjoy reading. While alone I don't have the TV or radio going. I don't need background noise.
While in my late 20's to early 30's I was divorced and lived alone for almost 5 years. All of my friends and family knew that just popping in to see me was not encouraged. Many times I just wanted to be alone.
A friend of mine cannot stand being alone, not even for an hour. He surrounds himself with people at all times. Quite often he will call and tell me that he has an errand to run asking me if I'd like to come with. It took me quite a few years to figure out that he isn't happy by himself.
At least twice a year I'll take a weekend and go camping/fishing by myself. Just kind of recharge my batteris I guess. While on those trips I go to places where it would be unusual to see another living soul. I enjoy that vey much.
Different strokes for different folks I guess.