During my study of happiness, I noticed something that surprised me: I often learn more from one person's highly idiosyncratic experiences than I do from sources that detail universal principles or cite up-to-date studies.

If you've had something for more than six months, and it's still not repaired, it's clutter.

I've noticed that the more I open up, the more I learn.

If I can do something in less than one minute, I don't let myself procrastinate. I hang up my coat, put newspapers in the recycling, scan and toss a letter. Ever since I wrote about this rule in 'The Happiness Project,' I've been amazed by how many people have told me that it has made a huge difference in their lives.

Enthusiasm is more important than innate ability, it turns out, because the single more important element in developing an expertise is your willingness to practice.

It's easy to be heavy; hard to be light.