What kind of tease are you?
You can't just going saying things like that and not giving more information on what you actually learned.
All right, lemme see. I downloaded abstracts for at least 400 studies directly or tangentially related to smiling. They're all on my old computer, which has been sitting in a drawer for about three years, so my memory is sketchy.
IIRC, though, a shockingly high number of these studies were written by dentists all searching for that Holy Grail, the mathematical formula that would enable them to create the perfect smile. They were trying to tweak this formula for calculating the optimal angle from one tooth to the next, in order to create the most appealing curve possible on something called the "buccal corridor."
Of course, this involved wearing braces, which made me think that wearing braces is nothing more than the late-20th and early-21st-century version of foot-binding. Smiling has become completely fetishized, yet another area in which individual differences must be minimized to the greatest extent possible. As for myself, my canines are unusually large, such that when I smile I look like a vampire. I'm not changing that for all the tea in China.
Speaking of China, there were also a lot of studies about how to create dimple implants. Apparently, at the time, this was the latest rage in cosmetic surgery among young Chinese career women. I come by my dimples naturally. My grandmother called them "fetching."
I can't remember any of the non-scary studies at the moment. Let me get back to you on that.
I also spent a lot of time trying to track down a quote by Quentin Crisp, from an op-ed column he wrote in the New York Times in the late 1970s or early 1980s. I had thought he said, "People who are truly happy do not need to smile," but that wasn't quite right. I did finally find the actual column somewhere, but I don't know what I did with it. Again, I'll gather all this information together and make a full presentation in the near future.
I could go off on a tangent about how I misremember quotes, especially movie quotes, but I'll save that for another time.