It took me a while to figure out where the “upside” bit of the title comes into things but I think I have grasped it now. Basically the book is a case for why we should be glad we don’t live in a society where everyone is like “Mr. Spock” and behaves only in a rational matter. The world is a better place because we trust other people (for example) even when it doesn’t make rational sense to do so. And then people, feeling trusted, often reward our trust…

The book is interesting, connected to real life, but not as interesting as the previous one (Predictably Irrational). More of the same, really.