Optimistic people play a disproportionate role in shaping our lives. Their decisions make a difference; they are inventors, entrepreneurs, political and military leaders - not average people. They got to where they are by seeking challenges and taking risks.

When action is needed, optimism, even of the mildly delusional variety, may be a good thing.

There is a huge wave of interest in happiness among researchers. There is a lot of happiness coaching. Everybody would like to make people happier.

The premise of this book is that it is easier to recognize other people's mistakes than your own.

Most of the time, we think fast. And most of the time we're really expert at what we're doing, and most of the time, what we do is right.

I used to hold a unitary view, in which I proposed that only experienced happiness matters, and that life satisfaction is a fallible estimate of true happiness.

It doesn't take many observations to think you've spotted a trend, and it's probably not a trend at all.