I don't know if it's just me but I've realised a lot of people that have social anxiety are also introverts and I think perhaps our fear stems from the fact that introverts aren't valued and excepted as much as extroverts are. We are expected to be like extroverts and put on a show else we are thought of negatively, that's bound to provoke anxiety. This also makes it a very difficult thing to overcome because you can't change your temperament or how people react to you... I don't think I would be as anxious if I was allowed to just be myself around people. I tend to avoid social situations because I know I will be thought badly of because I can't be like an extrovert. Perhaps it's just my own brain though, perhaps people don't mind introverts as much as I think they do?