I live in Thailand, the Land of Smiles, as it is often called. The Thais pride themselves of their easy, natural and beautiful smiles.
Many times I have gone out and felt touched by the wonderful smile of someone whom I had never seen and will probably never see again. It might have been a passerby on the street, a market vendor, or someone who stopped at a red light on their motorbike and flashed me one of those great Thai smiles.
What I love about the smiles in Thailand is that total strangers, including those of the opposite sex, will smile at you without ever feeling that this might be inappropriate or seductive or overly friendly.
Thais are normally quite shy people, but this is one area where there is no shyness and no hesitation at all. They give away the greatest smiles to anyone at any time and there does not have to be a reason or justification for it. This is the Land of Smiles, after all.