My writing model is my mother, who is a writer as well. She always valued clarity and simplicity above all else. If someone doesn't understand what you're writing, then everything else you do is superfluous. Irrelevant. If any thoughtful, curious reader finds what I do impenetrable, I've failed.

In fact, researchers have settled on what they believe is the magic number for true expertise: ten thousand hours.

The conventional wisdom is often wrong. Crime didn't keep soaring in the 1990s, money alone doesn't win elections, and - surprise - drinking eight glasses of water a day has never actually been shown to do a thing for your health. Conventional wisdom is often shoddily formed and devilishly difficult to see through, but it can be done.

David Epstein, the author of the best book on athletics in recent memory - "The Sports Gene" - wrote to me to say that he thinks I'm being overly generous. He points out that, for years, there used to be an "all-star challenge" on television, in which the best professional athletes from a variety of sports competed in a kind of makeshift decathlon.

Six degrees of separation doesn't mean that everyone is linked to everyone else in just six steps. It means that a very small number of people are linked to everyone else in a few steps, and the rest of us are linked to the world through those special few.

Outlier are those who have been given opportunities-- -and who have had the strength and presence of mind to seize them.

Happiness, in one sense, is a function of how closely our world conforms to the infinite variety of human preference.