Some scientists studied the longevity of baseball players using “college attendance, marital status, birth year, career length, age at debut year, and BMI.” This isn’t particularly interesting.
However, those scientists then repeated the study, only they included a player’s “smile intensity” the second time through (using baseball cards, I think). I have no idea how one measures smile intensity. Is there a chart? Some kind of luminosity scale? Brightness of teeth times the width of the grin raised to the power of the dimples? I’m really not sure, and I’m afraid it would detract from my enjoyment of smiling if I did know.
ANYWAY, as it turns out, a player’s smile accounted for 35% of the variability in their length of life. So smile and be happy. You’ll live longer.