ETA: found it by searching Jed's journal (the future is here!)

An interesting discussion. I'm a mixed introvert/extrovert and the comment that seemed the truest to me was the one that said, introverts go home and kick themselves over the things they *didn't* say, and extroverts go home and kick themselves over the things they *did* say. Uhuh. I have both those experiences pretty much all the time.

My main conclusion is that being a person is hard.