If I think of myself as a guest at an event, I tend to focus on myself and get passive. I focus on how bored I am, how difficult it is to go up and join ongoing conversations, how I always seem to get stuck with the most boring person in the room when I do try to converse, etc.
But if I think of myself as a host, then I see my role in a more active way. I do all the things a good host would do: Go meet and greet people just arriving at the event, engage others who are solitary and draw them in, circulate around the event and see that everything’s functioning smoothly, move on after 10 minutes in conversation with one person so that I can mingle and engage with others as well, take breaks to check my appearance and freshen up, etc.
Naturally I wouldn’t step on the toes of the real host of the event. It’s just a mind trick for changing my focus. I use my trick to get my focus off me and onto the people around me, and then I find that I lighten up and have more fun.
So basically I agree with you. Overthinking and overanalyzing one’s own performance is a hallmark of shy people, and shy people need to find ways to cut that out and move on. “A good time was had by all.” And that’s the end of it.