That describes me very well, except I am definitely not a busy person. I just don't like doing social things -- or rather I get a sort of malaise at the thought

That describes me very well, except I am definitely not a busy person. I just don't like doing social things -- or rather I get a sort of malaise at the thought of going to them, for exactly the reasons you describe here. I've honestly never seen it laid out this well before. But I don't think of it as social ineptitude, only because when I commit to doing things, I can be "on" and meet people and have a great time and all that. Beforehand, however, the thought of getting into that mentality and doing all that stuff seems like "work" to me, and I just feel like I don't wanna do it.