Psychology is much bigger than just medicine, or fixing unhealthy things. Its about education, work, marriage - its even about sports. What I want to do is see psychologists working to help people build strengths in all these domains.

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.

Doing a kindness produces the single most reliable momentary increase in well-being of any exercise we have tested.

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.

Some find that very optimistic people have benign illusions about themselves. These people may think they have more control, or more skill, than they actually do. Others have found that optimistic people have a good handle on reality. The jury is still out.

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

Curing the negatives does not produce the positives.