This sense of frustration and inappropriate anger seems to accompany most of my interactions with people of late, with a few notable exceptions. Strangers - probably because I try not to have complicated expectations about how strangers and I will interact. Maybe that's the key here - in sort of a parallel to 'suffering is caused by desire' I could resolve not to have expectations even of friends, since frustration seems to be caused by unmet expectations. But it also seems that part of what makes the label 'friend' apply to someone is a certain set of expectations regarding their behavior.
Oh well, this too shall pass.