Market segmentation matters. "It's critical to craft your message for a specific audience," - Peter Diamandis

1995 book Capitalism at a Crossroads: The Unlimited Business Opportunities in Solving the World's Most Difficult Problems, "[I]t is very difficult to remove cost from a business model aimed at higher-income customers without affecting quality or integrity."

dopamine, one of the brain’s primary pleasure drugs. We feel dopamine as engagement, excitement, a desire to investigate and make meaning out of the world. It’s released whenever we take a risk, expect a reward, or encounter novelty. Once hardwired into a reward loop — meaning, once our brain establishes a link between an activity and dopamine — the desire to get more of this chemical becomes our overarching preoccupation. Cocaine, by way of comparison, is one of the most addictive substances on Earth, yet much of what it does is flood the brain with dopamine

The best way to become a billionaire is to help a billion people.