Obvious but good to get confirmation. Anyone who's owned a dog knows that they can tell your mood in myriad ways, but this is the kind of basic research that is necessary to clear the way for more serious insights.

My dog knows my complete mood complex instantly every time I show up. It's a social/emotional intelligence unmatched by human. Unfortunatelly, or hopefuly for the human race, he cannot combine this ability with enough cognitive intelligence.