…quite simple, according to this: What do very happy people all have in common?.
Turns out, there was one—and only one—characteristic that distinguished the happiest 10 percent from everybody else: the strength of their social relationships.
In other words, you need friends! This is not surprising, of course, but it is nice to see the data. Go read the article for more on this.
In the wonderful children’s book series, Poppleton, there is a story about how the main character wants to live to be a 100. He learns from a wise old mouse that the secret to a long life is friends. Looks like it is the secret to happiness too. After all, the two go hand in hand.
And if you want a great series of books to read to kids, go see Poppleton And Friends by Cynthia Rylant , among others.