Throwing in another two cents here.

I'd say I lean toward introversion, though I've tried to spend a lot of time learning to engage in social situations, and do fairly well. I've been a full time trainer, and participated in various levels of managing teams to good success (if I do say so myself).

I like the people on my team, and I like going to lunch with them, but I hate Team Lunches. I think it has to do with how contrived the social situation feels, and how much I feel like someone is trying to push me into their vision of a sociable team.

One of my pet peeves is finding out someone wants to push Company Culture and that means getting everyone together to do cheers and chants.

There's nothing inherently wrong with cheers and chants and team lunches or whatever you want to do, but you love your job and who you work with and not want to be forced into a contrived social situation where you're supposed to bond. I bond just fine with my coworkers after we decide which thai place to go to on a given day.

Another commenter here, but I can relate - I like my coworkers and I'm sure they feel the same about me, but these birthday gatherings, christmas parties and other special occasions...well, I don't hate them, but comfortable is not a word I would use to describe them. It may sound like a cliche from the "introverts' manual", but when it comes to me, social interactions are preferred in small crowds, or even better, one on one.

It doesn't have to mean the he doesn't like other people as you seem to imply.