For me, being social is sort of like a switch that I can turn on and off.
I would consider myself to be, in the opinion of others, mostly anti-social. I am reasonably certain that most people probably think of me as anti-social, as some weird guy that keeps to himself mostly. I can live with that, because I've been naturally social in so many situations and no longer feel any need whatsoever to prove to myself or anyone else I might meet that I can be a normal extroverted social type. So I often choose to remain anti-social as opposed to social.
There's definitely not any need for me to frame my anti-social behavior as a disease or disorder, I have no delusions about why I am typically anti-social.
Whenever I was young I used to laugh a lot with friends, make in-jokes, we were often very loud like most kids our age. Something happened though, I think it was that I was unusually observant and began noticing that when other groups of children would be laughing loudly and making silly jokes, everything I observed them saying and doing sounded so stupid and annoying. This information, instead of remaining sort of egoistic with me thinking to myself, "When my friends and I are together we're all hilarious and absolutely not annoying, it's just other people", I realized that when I was with my friends being loud and making silly jokes, we were all absolutely very annoying and most of what we talked and joked about was just as stupid as what everyone else was talking and joking about. So, I became very self-conscious in a way, or rather, more self-critical than self-conscious. I realized that I was delusional about the social fabrication of which I was a part and that it was basically the same as the social fabrication of others of whom I was very critical. I've always had a serious frame of mind, even while at my most jovial and entertaining.
While it took many years for this epiphany to really sink in deep and permanently alter my social behavior (in a way not so awkward as when I first came to this realization), I did become a lot more anti-social... maybe asocial would be a better way of describing it. I am certainly not anti-social according to my own personal definition of what it means to be anti-social, but I would definitely say I am asocial. I am definitely not against the concept of social interaction and communication, I thrive on it really. I even see the folly in my previous thinking, that making silly jokes and having a laugh is not a bad thing in all honesty, I just had to develop a lot more humility to realize where I erred.
So, back to the switch concept. I still consciously decide to remain asocial rather than social, and for many reasons. The primary reason is that in America today, or at least in the part of America that I live, I find the vast majority of all social interaction that takes place completely repugnant, devoid of any meaning whatsoever. Humorous conversations are even beginning to seem lackluster, since so many people's senses of humour revolve around quoting one-liners from movies, being "random", etc. I get sick of small talk, I do not wish to contribute to any modern discussions of artless television soaps or sports-spectacles, none of it interests me to even a miniscule extent, and I would much rather be thought of as that weird guy that can't or won't talk to anybody than to contribute to bland social discourse. It's as simple as that, really.
Of course, there are both positive and negative by-products of asocial and anti-social behavior. I think that the negative by-products are typically construed as being the cause of asocial and anti-social behavior, and find myself in disagreement with the professionals that prescribe drugs to combat these avoidances of the social by targeting the effects of the life-style, such as fear of crowds, soft-speech / mumbling, inwardness, fidgeting, depression, etc.
It was a deliberate change of my personality, and I can go back and forth on it depending on what suits me at the moment.