when I see my german shepard's teeth, it ain't because she is happy...
how do you smile with your teeth? you mean showing your teeth? I thought it means really happy, don't do that to a dog though
Sometimes it looks like I'm smiling when I'm in a lot of pain, but like Rodney said, a smile shows up in the eyes.
Meaning comes from the emotional experience and radiates outward in your own manner(s)(isms). It is different per person. For example if I feel flattered I don't smile like that, I look away or become shy about my behavior while some others will take some victory pose like they won a game.
You can't really expect a general response from all the people, they are too diverse for that.
I'm glad for it :)
It can mean anything
When I do that on purpose, it means I am faking a smile.
I've seen it mean the opposite a lot of times. I don't think it's got to do with the teeth. You can tell from the eyes, can't you?