Now do you reckon your pet knows when you're in a good or bad mood? And can they figure out the different faces you pull?
Well scientists think they can.
Dogs can tell the difference between happy and angry human facial expressions, a study has revealed.
Researchers from the University of Vienna, Austria, ran an experiment where 11 dogs were trained to pair either a happy or an angry face with a food reward.
Leah's been finding out more.
Footage courtesy of Clever Dog Lab, Messerli Research Institute