@dlowan,
I was going to blame the time of year -- I was just having a conversation with a teacher who said that the kids are always crabby and irritated and sniping at each other this time of year. They're cooped up and tired of winter and spring keeps teasing only to be followed by cold and dreariness. (The Drama quotient in sozlet's social life has recently been upped considerably, apparently that's universal right now.)
But that doesn't work for those upsidedowners. Hmm.
Maybe it's just general weariness with the season, ready for a change of pace? I think people get crabby here in August too and welcome the first cool breezes of September...