However, optimism is highly valued, socially and in the market; people and firms reward the providers of dangerously misleading information more than they reward truth tellers. One of the lessons of the financial crisis that led to the Great Recession is that there are periods in which competition, among experts and among organizations, creates powerful forces that favor a collective blindness to risk and uncertainty.

The premise of this book is that it is easier to recognize other people's mistakes than your own.

We were required to predict a soldier's performance in officer training and in combat, but we did so by evaluating his behavior over one hour in an artificial situation. This was a perfect instance of a general rule that I call WYSIATI, "What you see is all there is." We had made up a story from the little we knew but had no way to allow for what we did not know about the individual's future, which was almost everything that would actually matter. When you know as little as we did, you should not make extreme predictions like "He will be a star."

Our comforting conviction that the world makes sense rests on a secure foundation: our almost unlimited ability to ignore our ignorance.

One thing we have lost, that we had in the past, is a sense of progress, that things are getting better. There is a sense of volatility, but not of progress.

The dominance of conclusions over arguments is most pronounced where emotions are involved.

People just hate the idea of losing. Any loss, even a small one, is just so terrible to contemplate that they compensate by buying insurance, including totally absurd policies like air travel.