I think the fact that the majority of people here have replied 'I spend a lot of time on my own' means that we seem to think that spending 'a lot' of time on our own is something unusual, when in fact, it's not. Very few people will want to be surrounded by people all the time, and it's natural that even the most sociable people will spend at least a good few hours per day alone, particularly when you're young and not married/living with someone.
I go out/see people a few times a week, and this is basically all the socialising I need. When I'm at home, I'll gladly stay in my room most of the day anyway; the only 'family' activity available to me is watching television, and I don't really watch any at all.