Well, it is definitely worse with strangers than with close friends....
It's not really the proximity to crowds that does it -- it's when I feel like the crowd is looking at me. Case in point, I went to NYC once and stayed in Times Square. I was really worried about it, but once I was there, even though it was crowded, it felt like nobody noticed me, and I didn't have any trouble.
But when I go to Bellevue Square mall, for example, it feels like everybody is looking at me, and everybody is so close and crowded and judging me and in my face....
I have absolutely no control over it. There doesn't seem to be any analytical reasoning behind it or anything; it's like an allergic reaction that I can't stop. My brain is wired funny or something.
CC.com doesn't really do that to me, you guys feel like family