In this TED talk, psychiatrist Robert Waldinger describes the results of a study he directs at Harvard where they have tracked over 700 men for 75 years to find out what actually makes us happy. Not surprisingly, what they found is that good relationships keep us happy, and healthier. People who are more socially connected, they have found, are happier, physically healthier, and live longer. People who are more isolated than they want to be find they are less happy and their health declines earlier. Also, Waldinger says, it's not just the number of relationships, but the quality of relationships that matter. He reminds us that while we would all like a quick fix for happiness, relationships can be messy and take work, but it's that work that can make for a rewarding life.