It's a matter of ABC: When we encounter ADVERSITY, we react by thinking about it. Our thoughts rapidly congeal into BELIEFS. These beliefs may become so habitual we don't even realize we have them unless we stop to focus on them. And they don't just sit there idly; they have CONSEQUENCES.

The pleasant life: a life that successfully pursues the positive emotions about the present, past, and future.

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

Habits of pessimism lead to depression, wither achievement, and undermine physical health. The good news is that pessimism can be unlearned, and that with its removal depression, underachievement, and poor health can be alleviated.

To the scientists of the Renaissance, your critic was really your ally, helping you advance upon reality. Critics in science are not like drama critics, determining flops and successes. Criticism to scientists is just another means of finding out whether they're wrong, like running another experiment to see if it confirms or refutes a theory. Along with the advocacy principle of the courtroom, It is one of the best ways human beings have evolved to get closer to the truth.

Positive emotion can be about the past, the present, or the future. The positive emotions about the future include optimism, hope, faith, and trust. Those about the present include joy, ecstasy, calm, zest, ebullience, pleasure, and (most importantly) flow; these emotions are what most people usually mean when they casually-but much too narrowly-talk about "happiness." The positive emotions about the past include satisfaction, contentment, fulfillment, pride, and serenity.

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