Political columnists and sports pundits are rewarded for being overconfident.

The illusion that we understand the past fosters overconfidence in our ability to predict the future.

The idea that the future is unpredictable is undermined every day by the ease with which the past is explained.

Optimistic people play a disproportionate role in shaping our lives. Their decisions make a difference; they are inventors, entrepreneurs, political and military leaders - not average people. They got to where they are by seeking challenges and taking risks.

Unfortunately, skill in evaluating the business prospects of a firm is not sufficient for successful stock trading, where the key question is whether the information about the firm is already incorporated in the price of the stock. Traders apparently lackthe skill to answer this crucial question, but they appear to be ignorant of their ignorance.

If there was one ubiquitous recommendation about marriage it was this: "Don't go to bed angry."

I have always emphasized the willingness to discard.