Can pets read human emotions?

I definitely think my dogs can read my emotions. They'll come and comfort me when I'm sad and they're always happy and excited when I'm in a good mood. I'm not so sure about other species. My cats sometimes seem to be in tune with my emotions but other times not, sometimes they're really quite annoying when I'm not in the mood but they won't take no for an answer. They seem to know when I'm trying to do something though, that's when they want my attention!