A hefty body of research has found that an overwhelmingly strong predictor of happiness and well-being is the quality of a person's social relationships. But most of the studies have only looked at close ties. In the past 15 years, researchers have begun to wonder if interacting with strangers would be good for us too - not as a substitute for close relationships, but as a complement to them. The results of the research are striking; again and again, studies have shown that talking to strangers can make us happier, more connected to our communities, mentally sharper, healthier, less lonely and more trustful and optimistic. So why don't we talk to strangers more often? This is influenced by many factors, but at the core are two reasons: We don't expect strangers to like us, and we don't expect to like them either. However, in study after study, people had positive interactions with strangers and experienced many benefits. So, why not give it a try next time you're standing in line somewhere?