Also, I find it far easier to be in company when it's not all about the socialising. If that makes any sense. When we're doing something practical together or concentrating on something instead of just talking and talking in an open-ended way, that takes the pressure off somehow.
At one extreme: going to the cinema is easy because, though there's lots of people, we're not really interacting. A lot of my social life involves live music, where I'll be either listening to the music or playing myself, so it's OK not to spend the whole time talking to people. I also go to a Bookcrossing meeting- we all bring old books along to swap, and it seems to be acceptable to drift away from the conversation to look through the books for a while.
These are situations where I can spend three or four hours with some effort but without completely messing up my head. I no longer even try to go to anything called a "party," but eating out for a friend's birthday is manageable- I know there'll be food to concentrate on at regular intervals!
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You're so vain
I bet you think this sig is about you