Jenny Simpson loses her shoe in the women's fifteen hundred, with a lap and a half to go, destroying her chances to repeat as world champion, and she gives the most gracious interview afterward about how she's had a wonderful career already. Great for Jenny Simpson. Bad for the sport! We need drama!

What a gifted child is, in many ways, is a gifted learner. And what a gifted adult is, is a gifted doer. And those are quite separate domains of achievement.

I don't like things that aren't true.

Economists often talk about the 80/20 Principle, which is the idea that in any situation roughly 80 percent of the “work” will be done by 20 percent of the participants. In most societies, 20 percent of criminals commit 80 percent of crimes. Twenty percent of motorists cause 80 percent of all accidents. Twenty percent of beer drinkers drink 80 percent of all beer. When it comes to epidemics, though, this disproportionality becomes even more extreme: a tiny percentage of people do the majority of the work.

Our intuitions, as humans, aren't always very good. Changes that happen really suddenly, on the strength of the most minor of input, can be deeply confusing.

People are experience-rich and theory-poor.

Once a musician has enough ability to get into a top music school, the thing that distinguishes one performer from another is how hard he or she works. That's it. And what's more, the people at the very top don't work just harder or even much harder than everyone else. They work much, much harder.