It's rather silly, actually. The first band had dancers on the floor, in period burlesque/cabaret garb, and they were totally great, funny, and amazing dancers to boot. I really enjoyed watching them. There were a few times when they came into the crowd, doing a camp routine, and a couple of times they came very close to where I was standing, which was when I was supposed to "engage" them and partake in the act, same as when it happened to anyone else in the crowd. There wasn't any touching or anything. Everyone else was laughing and playing along, but I at first just shyly looked towards the ground and didn't do anything. The few more times it happened, I started to freak out, and say in my brain "get the fuck away from me!" I wasn't mad at them or anything, but I was having this physical and emotional reaction totally contrary to the situation.
I think it was this combination of closeness and having a certain (albeit small) degree of focus placed on me, especially because I was around new acquaintances who I wanted to befriend, so there was that added social discomfort.
Anyway, I got the fuck out of there double-quick and had a smoke.
Laugh all you want, all I have to say is, it's weird what can set you off.
I remember reading that thread of yours. I think my therapist years ago did some couples therapy with my then girlfriend, and she wanted for us to sit facing each other, and I said after the fact that I didn't like doing that. It didn't cause a flashback like this did, but it was certainly uncomfortable, so I certainly understand about the sitting down thing. I was adverse to group therapy for years for that very reason. i.e. sitting in a circle.