I have to wonder if there is an expectation from those cliques that us reserved types will come more out of our shell when we go out with them. Years ago, I went along with a work group that invited me out, and at the end of the evening, one of my coworkers said he thought I would have opened up more. It wasn't particularly mean sounding, but I felt horrible.

So I do wonder if there's almost a sense for them that we pay a transaction. They invite us out, and in return, they expect us to loosen up more. I dunno. Just one of many theories. I'm at the same point you are, where I just stopped going out with groups. Give me a nice, quiet one-on-one any day.