The psychologist, Paul Rozin, an expert on disgust, observed that a single cockroach will completely wreck the appeal of a bowl of cherries, but a cherry will do nothing at all for a bowl of cockroaches.

Finally, the illusions of validity and skill are supported by a powerful professional culture. We know that people can maintain an unshakeable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers. Given the professional culture of the financial community, it is not surprising that large numbers of individuals in that world believe themselves to be among the chosen few who can do what they believe others cannot.

Except for some effects that I attribute mostly to age, my intuitive thinking is just as prone to overconfidence, extreme predictions, and the planning fallacy as it was before I made a study of these issues.

We are prone to overestimate how much we understand about the world and to underestimate the role of chance in events.

Employers who violate rules of fairness are punished by reduced productivity, and merchants who follow unfair pricing policies can expect to lose sales.

People like leaders who look like they are dominant, optimistic, friendly to their friends, and quick on the trigger when it comes to enemies. They like boldness and despise the appearance of timidity and protracted doubt.

We're generally overconfident in our opinions and our impressions and judgments.