If you look at the careers of great entrepreneurs and you look at the moment they took their plunge, the plunge is rarely a great financial or material risk, it’s a social risk. At the moment they started their new businesses, everyone around them said ‘you’re an idiot’.

The key to good decision making is not knowledge... It's whether our work fulfills us.

For every romantic possiblity, no matter how robust, there exists at least one equal and opposite sentence, phrase, or word capable of extinguishing it.

Re-reading is much underrated. I've read The Spy Who Came in from the Cold once every five years since I was 15. I only started to understand it the third time.

We spend a lot of time and effort trying to figure out who's going to be a good NFL quarterback, and we do a very bad job of it. We don't really know. And we also spend a lot of time trying to figure out who will be a good teacher, and we're really bad at that too. We don't know if someone is going to be a good teacher when they start teaching. So what should we do in those situations in which predictions are useless?

You can't concentrate on doing anything if you are thinking, “What's gonna happen if it doesn't go right?

A study at the University of Utah found that if you ask someone why he is friendly with someone else, he’ll say it is because he and his friend share similar attitudes. But if you actually quiz the two of them on their attitudes, you’ll find out that what they actually share is similar activities. We’re friends with the people we do things with, as much as we are with the people we resemble. We don’t seek out friends, in other words. We associate with the people who occupy the same small, physical spaces that we do.