Yes, dogs smile when they're happy (and frown when they're sad or if we are sad).
Dogs grin by pulling back the corners of their lips and baring their teeth. A very relaxed dog will smile and then close his eyes.
(Don't make the mistake of confusing a grin with a snarl. If a dog has his mouth pulled back, but is showing his incisors and back teeth, most likely he's snarling.)
All dogs smile, which is to say their faces become pleasant and relaxed, with ears low, eyes half shut, lips soft and parted, and chin high. This is a dog smile.
I totally agree with you!! my dogs do smiles in front of the camera, and same to my friend's golden. but i seldom see the puppy in the petshop smiles..., even they are happily play with their mates behind the glass....
anyone seen puppy in the petshop smiles? if yes, please bring back that puppy, the puppy must be a happy go lucky pup!