The pursuit of happiness is enshrined in the Declaration of Independence as a right of all Americans, as well as on the self-improvement shelves of every American bookstore. Yet the scientific evidence makes it seem unlikely that you can change your level of happiness in any sustainable way. It suggests that we each have a fixed range for happiness just as we do for weight. And just as dieters almost always regain the weight they lose, sad people don't become lastingly happy, and happy people don't become lastingly sad.

Success requires persistence, the ability to not give up in the face of failure. I believe that optimistic explanatory style is the key to persistence.

In a society in which individualism is becoming rampant, people more and more believe that they are the center of the world. Such a belief system makes individual failure almost inconsolable.

Not only do happy people endure pain better and take more health and safety precautions when threatened, but positive emotions undo negative emotions.

The defining characteristic of pessimists is that they tend to believe that bad events will last a long time, will undermine everything they do, and are their own fault. The optimists, who are confronted with the same hard knocks of this world, think about misfortune in the opposite way. They tend to believe that defeat is just a temporary setback or a challenge, that its causes are just confined to this one case.

One of the things psychologists used to say was that if you are depressed, anxious or angry, you couldn't be happy. Those were at opposite ends of a continuum. I believe that you can be suffering or have a mental illness and be happy - just not in the same moment that you're sad.

Well-being cannot exist just in your own head. Well-being is a combination of feeling good as well as actually having meaning, good relationships and accomplishment.