I think a lot of social interaction is a bit overstimulating for me - it doesn't turn to mania but it seems to hasten hypomania. Most of the time an intense social situation co-occurs with other factors that seem to trigger hypomanic episodes for me, so I can't say it's one thing or the other.

It does take me a minimum of 2 hours to calm down enough to try to sleep after intense social interaction (hubby excepted, he has a nice soporific effect and helps me fall asleep faster!) From talking with other "normal" friends that seems a bit more than most people need for down time after socializing, so if that's any indication...