If we just wanted positive emotions, our species would have died out a long time ago.

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.

When it comes to our health, there are essentially four things under our control: the decision not to smoke, a commitment to exercise, the quality of our diet, and our level of optimism. And optimism is at least as beneficial as the others.

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

To be a virtuous person is to display, by acts of will, all or at least most of the six ubiquitous virtues: wisdom, courage, humanity, justice, temperance, and transcendence.

Changing the destructive things you say to yourself when you experience the setbacks that life deals all of us is the central skill of optimism.

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.