If owning stocks is a long-term project for you, following their changes constantly is a very, very bad idea. It's the worst possible thing you can do, because people are so sensitive to short-term losses. If you count your money every day, you'll be miserable.

One of the problems with expertise is that people have it in some domains and not in others.

So your emotional state really has a lot to do with what you're thinking about and what you're paying attention to.

People talk of the new economy and of reinventing themselves in the workplace, and in that sense most of us are less secure.

Organizations may be better able to tame optimism than individuals are.

Divorced women, compared to married women, are less satisfied with their lives, which is not surprising. But they're actually more cheerful, when you look at the average mood they're in in the course of the day.

We were required to predict a soldier's performance in officer training and in combat, but we did so by evaluating his behavior over one hour in an artificial situation. This was a perfect instance of a general rule that I call WYSIATI, "What you see is all there is." We had made up a story from the little we knew but had no way to allow for what we did not know about the individual's future, which was almost everything that would actually matter. When you know as little as we did, you should not make extreme predictions like "He will be a star."