There are several possibilities for a dog to lick its owner’s hand. One is that the dog is expressing his love for his owner and is releasing his goodwill to you by licking. Two, the dog is hungry or thirsty and it is alerting you to feed it. Three is that it finds you in a bad mood in comforting you, dogs are a very sensitive animal to emotions, you are not happy it is aware of, it will comfort you through their own way.
