We don't see very far in the future, we are very focused on one idea at a time, one problem at a time, and all these are incompatible with rationality as economic theory assumes it.

To know whether you can trust a particular intuitive judgment, there are two questions you should ask: Is the environment in which the judgment is made sufficiently regular to enable predictions from the available evidence? The answer is yes for diagnosticians, no for stock pickers. Do the professionals have an adequate opportunity to learn the cues and the regularities? The answer here depends on the professionals' experience and on the quality and speed with which they discover their mistakes.

In essence, the optimistic style involves taking credit for successes but little blame for failures.

It's a wonderful thing to be optimistic. It keeps you healthy and it keeps you resilient.

To better avoid errors, you should talk to people who disagree with you and you should talk to people who are not in the same emotional situation you are.

If people do not know what is going to make them better off or give them pleasure, then the idea that you can trust people to do what will give them pleasure becomes questionable.

There's a tendency to look at investments in isolation. Investors focus on the risk of individual securities.