Stumbling on Happiness summary This is my book summary of Stumbling on Happiness by Dan Gilbert. My notes are informal and often contain quotes from the book as well as my own thoughts. This summary also includes key lessons and important passages from the book. The greatest ability of the human brain is to imagine, to see the world as it has never been before. “What makes humans different from every other animal is that they think about the future.” Our brain makes predictions incredibly quickly and about nearly everything in life. When our experiences don't match what our brain expects, we feel surprised. The frontal lobe is responsible for planning and anxiety — two key future-oriented functions. Our frontal lobe is what allows us to be the only animal that experiences and envisions the future as we do. We like to daydream because the mere dream itself can be a joy. Within a few weeks even earthquake survivors tend to return to previous levels of optimism. If we don