In Anneli Rufus' expose on some of the interesting, yet freakily unusual, statistics on divorce and marital success, she reveals that a person who never smiled in yearbooks in high school are five times more likely to have a marriage end in divorce than if you 'smiled intensely in photographs'.
Rufus explains [Via The Daily Beast]:
Two tests, the first involving college yearbook photos and the second involving miscellaneous photos taken during participants' youths, yielded this finding. "People who are optimistic— and that's what smiles tend to show in childhood—find it easier to get along with people," including the people they're married to, asserts Coontz, who is also the author of Marriage: A History. Optimistic types "also find it easier to put up with periods in life that might be difficult." Nonetheless, she warns: "Optimism is certainly not going to protect you from everything, so it's no guarantee."
