The difference for me is that I experience social anxiety differently than I experience being inherently a socially square peg in a round hole. A large part of my social experience is that people expect me to be a different person than I am and behave in a different way than I feel comfortable. That’s a very different feeling from how I experience social anxiety or otherwise feel shy. It’s essentially a performance, often called masking, and I have a different (quite a bit less usually) capacity for it than I do all of the challenges of being socially engaged when I’d rather not for my own space.