My dog has three smiles.
He has a goofy one that he usually has.(He's always happy).
He has one where he shows his front teeth only, that's when he's just woke up. (Someone said the other day: I think your dog just smiled at me).
Then he has one that he only does when we're just sitting together somewhere and it's been a great day, he lays his head on his paws.
( I love that smile)