Sometimes, it feels like we run into rude – or even hostile - strangers everywhere we turn, whether we’re behind the wheel, in line at the grocery store, or sitting in the stands at a ballgame. A recent survey found that almost 4 out of 5 people believe that others are less polite than they were just a few years ago. But there’s an easy way to stem the tide of bad behavior around you - and even spread some goodwill: Smile.

According to a study in the journal Psychological Science, seeing a smile instantly improves the mood of the person smiling, and everyone who sees that smile. More importantly, smiling at someone who’s angry can instantly calm them down and reduce their aggression.

And the reason’s simple: We’re hardwired to mirror the people we’re with, so, when we see a smile, we feel compelled to smile back. Even smiling when we don’t feel like it increases production of stress-lowering, mood-boosting hormones. And according to psychologist Dr. Jessica Tracy, smiling makes other people see us as friendly, attractive, and intelligent, which makes them more likely to like us.