Well...my goodness...I have done that a lot! I have gradually stopped doing it, but only after a lifetime of self-reflection! I totally agree with you that it is a form of social anxiety. I actually have a few friends who accept me and seem to love me, despite this. But in most social situations, I am insecure and feel very uncomfortable. I did observe that while I was in grad school in Art, that those fellow grad art students (much younger than me) seemed to love and accept me. This was surprising! I'm no longer around those students, but it helped me realize there are people who accept you for what you are! Perhaps the key is to find people who are like-minded. Nowadays, in my work as a teacher, I rarely interact personally, and just keep to myself.
Patty