Optimism is a tool with a certain clear set of benefits: it fights depression, it promotes achievement and produces better health.

By activating an expansive, tolerant, and creative mindset, positive feelings maximize the social, intellectual, and physical benefits that will accrue.

On the relationship side, if you teach people to respond actively and constructively when someone they care about has a victory, it increases love and friendship and decreases the probability of depression.

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.

What determines how much time and deliberate practice a child is willing to devote to achievement? Nothing less than her character.

I believe that traditional wisdom is incomplete. A composer can have all the talent of Mozart and a passionate desire to succeed, but if he believes he cannot compose music, he will come to nothing. He will not try hard enough. He will give up too soon when the elusive right melody takes too long to materialize.

Ten years ago, when I was on an airplane and I introduced myself to my seatmate, and told them [I was a psychologist], they'd move away from me. ... And now when I tell people what I do, they move toward me.