I'm Not A Great Believer In Self-help.

The Idea That You Can Ask One Question And It Makes The Point - Well, That Wasn't How Psychology Was Done At The Time.

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.

When Action Is Needed, Optimism, Even Of The Mildly Delusional Variety, May Be A Good Thing.

The Amount Of Success It Takes For Leaders To Become Overconfident Isn't Terribly Large.

A General Limitation Of The Human Mind Is Its Imperfect Ability To Reconstruct Past States Of Knowledge, Or Beliefs That Have Changed. Once You Adopt A New View Of The World (or Any Part Of It), You Immediately Lose Much Of Your Ability To Recall What You Used To Believe Before Your Mind Changed.