I understand.

I can run a talent show and be totally at ease. The focus isn't on "me" even though I'm the center of attention while I'm on the stage. The attention is on what's coming up - on whatever kid I'm talking about. When you're on stage, the attention is on the song and there's other people to have a focus on. I totally get it.
How do you do if you're the center of attention at a birthday party? I would flip out.
I also do great when meeting new people and having small talk. I break down when it comes to actually being ME and trying to build trust and a friendship. It'll take me months of "Yeah, we should do something!" before I actually do something with the person.
I actually do quite well in crowds (some types of crowds). Like... I can be in the middle of a busy street, mall, park, etc.. and I'm fine. I blend in with the crowd and I can leave whenever I want. But put me in a concert and I'm an anxious because I feel trapped. Put me in the cinema or theatre or restaurant and I need to have at least one side of me that feels "ok".. so a wall or aisle needs to be near me, so that I feel like I can leave.