Happier children are more likely to grow into successful and accomplished adults. Happiness is a huge advantage in a world that focuses on productivity. On average, happy people are more successful than unhappy people, both in work and in love. They get higher performance ratings, have more prestigious jobs, and earn higher wages. They are more likely to marry, and once married, they are more satisfied with their marriage.

So, looking at the science, what really works when it comes to raising happy kids? Want to avoid interacting with a sullen teenager? Then teach these teenagers to look on the bright side. Ten-year-olds who are taught to think and interpret the world optimistically are half as likely to be depressed when they hit puberty. Writer Christine Carter puts it simply: “Optimism is so closely associated with happiness that they can almost be equated.”