Sometimes I get a bit annoyed when my sims turn tense (if not furious) for no apparent reason, until I notice that in the place where they are there is a stereo playing a music genre they dislike (so that I always play with music off to listen to my own music, I never notice it until it's too late...)
Inspired mood getting replaced by tense when my sims are about to finish painting something or writing a novel also annoys me a bit, I have the impression that this makes them produce worse paintings and novels when it happens...