> Ironically, optimism-- or at any rate, the will to keep on going-- is one of the best predictors I know of success-- and not just in business.
This is not what I have observed. The most successful in business people I know personally are pessimists. In one particular case the pessimism made the guy to prepare for the worst. That allowed for him to survive bad times and gain from the good times disproportionally.
Another example is a very optimistic guy who quieted his job as an oil engineer and went to Thailand to start a shrimp farm. It was rather successful initially. But one day a drunken worker from the factory got into a conflict with local mobs and they burn the farm down... Now the guy is back into his engineering position.