It's not a case of: 'Read this book and then you'll think differently. I've written this book, and I don't think differently.

The amount of success it takes for leaders to become overconfident isn't terribly large.

If people are failing, they look inept. If people are succeeding, they look strong and good and competent. That's the 'halo effect.' Your first impression of a thing sets up your subsequent beliefs. If the company looks inept to you, you may assume everything else they do is inept.

People who are cognitively busy are also more likely to make selfish choices, use sexist language, and make superficial judgments in social situations.

That's one of the real dangers of leader selection in many organizations: leaders are selected for overconfidence.

Most people are highly optimistic most of the time.

Some achieve a reputation for great successes when in fact all they have done is take chances that reasonable people wouldn't take.