SoMuchForSubtlety and Buffy - I also moved around a lot as a child (seven primary schools and a year of home ed) and it got to the point where I just didn't bother interacting with the other children any more - what was the point in making friends if we were just going to move in a couple of months anyway? I'm very introverted to start with so social interactions are hard work for me. When we finally stopped moving, I didn't realise that it was our "final stop" as were, so as usual, I hadn't bothered making friends and then was stuck the next 8 years with children who had formed an opinion of me as a weirdo who didn't talk to people and was instead rather rude. So I was absolutely socially inept when I left school. I didn't know how to interpret tone of voice, body language, subtlely - you had to tell me things exactly as they were or I wouldn't understand. University was no better, I made very few friends as I was so "rude" - never intentionally, I just didn't know how to talk to people.
Eventually I worked in a pub where I used my time to really watch how people interacted and read lots of books on body language. One of the other staff there was, well, how to describe her? She was popular, knew how to socialise and was kind enough, but also blunt and took no bollocks, so she would tell me when I was cocking up socially. It was actually hugely helpful! I was much better after working there, and more able to interact with people, though I never initiated any conversations or friendships. At parties etc I'd still just stand in the corner and not talk to anyone unless they approached me. DH is unfortunately the same, so when we went out together we'd be a pair of wallflowers. His excuse is that he's a twin, so they always had each other, and because of that he reckons he also missed out on a lot of learning to interact with people who weren't his brother.
Living in Israel also helped. They're a very blunt people, so I fit right in with my less-than-subtle manners. In fact, they thought I was rather reserved! It was such a relief to me to find out that the British way of never quite saying what you mean was just a British thing - it wasn't universal and I wasn't unique in wondering why people don't just say what the fuck they mean. I felt so much at home there; I wasn't the weirdo with no manners, I was just normal.
But I think it was an MN meet-up that finally got me to put myself out there. I went to one where I knew no-one and made myself flit about from group to group, being a social butterfly, talking to everyone. It was absolutely performative, but so wonderfully liberating. And now I'm quite happy to just go up to people and start chatting.
It's taking me until the age of 40, though, to teach myself how to behave in public without making a complete tit of myself. It has been a very hard slog. I don't know if I'm slightly on the ASD spectrum; I'm certainly at the spectrum end of people who aren't on the spectrum, if that makes sense. I'm still a raging introvert and my mental health suffers hugely if I don't get a lot of time alone.
Wow, that got long. TL:DR - yes, I totally get what you mean by "performing" normal social interactions. I do it too. But it is becoming more natural to me the more I do it, even though I was a late starter!