You knew those stiff-faced yearbook photos would come back to haunt you one day. But this one’s unexpected: Women with “low intensity” smiles in their childhood and college photos are five times likelier to get divorced as adults than those who smiled effusively, found a 2009 study at DePauw University. A bright, wide smile represents an underlying positive disposition and worldview—undoubtedly helpful in marriage
. Lifelong smilers may be the type to seek and sustain lasting relationships, and because smiling is contagious, their partners may be happier too. The good news about smiling: If you want, you can “fake it ‘til you make it.” As we know from the facial feedback theory of emotion, smiling deliberately—even if you need to put a pen between your lips to get your lips to turn that way—can make you feel happier, because facial expressions influence emotions.