Here's one tip you pet owners should all know about. Dogs communicate their feelings through smell. You have to be a dog to get the full nuances of the smells, and the best place is in the butt. A dog sniffing another dog's butt is basically asking "how are you doing?".

Humans can learn to recognize some of the smells, and without smelling a dog's butt. Oddly enough, the bad smells usually mean a bad mood, and the good smells mean a good mood, at least with my dog. Just pay attention to the smell of your dog at various times and you'll learn to recognize it. The most recognizable smells in my dog are the "fear" and "happy" smells. She gets the strongest "happy" smell when my wife is getting ready to take her for a run, and the "fear" smell I've noticed strongest when she's been attacked by another dog.

The point is, dogs really do communicate how they're feeling, we just don't know how to "listen".