Lower your cortisol level. The happiest people have the lowest level of cortisol, a stress hormone that raises blood pressure and weakens the immune system. Cut the stress-more yoga, less road rage-and you'll cut your cortisol production.

Your mistake was not in imagining things you could not know—that is, after all, what imagination is for. Rather, your mistake was in unthinkingly treating what you imagined as though it were an accurate representation of the facts.

Because your brain uses information from the areas around the blind spot to make a reasonable guess about what the blind spot would see if only it weren't blind, and then your brain fills in the scene with this information. That's right, it invents things, creates things, makes stuff up! It doesn't consult you about this, doesn't seek your approval. It just makes its best guess about the nature of the missing information and proceeds to fill in the scene.

Lower your cortisol level. The happiest people have the lowest level of cortisol, a stress hormone that raises blood pressure and weakens the immune system. Cut the stress-more yoga, less road rage-and you'll cut your cortisol production.

The human brain is the only object in the known universe that can predict its own future and tell its on fortune. The fact that we can make disastrous decisions even as we foresee their consequences is the great, unsolved mystery of human behavior. When you hold your fate in your hands, why would you ever make a fist?

The truth is, bad things don't affect us as profoundly as we expect them to. That's true of good things, too. We adapt very quickly to either.

If someone offered you a pill that would make you permanently happy, you would be well advised to run fast and run far. Emotion is a compass that tells us what to do, and a compass that perpetually stuck on north is worthless.