A warm smile is the universal language of kindness. — William Arthur Ward
In both the Marginal Revolution post, Don't smile too much, and the original New York Times' TierneyLab post, Solved: The Mystery of the Miserable Models, and their attendant comments, are some enlightening observations on why not smiling is associated with higher class, quality, expense, power, and dominance. Sad commentary as that is, it fits in with two other experiences that have come to mind recently.
When my mother worked as a teacher's aide in an elemenary school, she tried to call attention to the plight of a small child of Asian origin who was being harrassed by the other students. The teacher would not take her seriously, because in her view the boy must be happy, since he was smiling all the time. My mother—correctly, I'm sure—interpreted those smiles as cringing deference, masking fear.
I was talking with a British friend, who lives in France, and his observation was that many Europeans view a person who smiles at strangers as either mentally unbalanced or a prostitute!
Having so recently read Meic Pearse's analysis of Western anticulture, I can't help seeing a connection between a meaningless culture of consumption and entertainment, such as pervades Europe, Canada, the United States, and other places with a great "Western" influence, and the loss of smiling, innocent happiness. (Not to say that this anticulture is common amongst "real people" in any country; but to many, what is rampant in Hollywood, the news media, and academia is perceived as reality, and may indeed be becoming so.)