So your emotional state really has a lot to do with what you're thinking about and what you're paying attention to.

It's not a case of: 'Read this book and then you'll think differently. I've written this book, and I don't think differently.

We know that the French are very different from the Americans in their satisfaction with life. They're much less satisfied. Americans are pretty high up there, while the French are quite low - the world champions in life satisfaction are actually the Danes.

Ten minutes of a smartphone in front of your nose is about the equivalent of an hour long walk in bright daylight. Imagine going for an hour long walk in bright daylight and then thinking, "Now I'll get some sleep." It ain't going to happen.

Optimism is normal, but some fortunate people are more optimistic than the rest of us. If you are genetically endowed with an optimistic bias, you hardly need to be told that you are a lucky person - you already feel fortunate.

We're generally overconfident in our opinions and our impressions and judgments.

The extra daily social time of 1.7 hours in weekends raises average happiness by about 2%.