Emotion is contagious.

Courage is what you earn when you've been through the tough times and you discover they aren't so tough after all.

Truly successful decision-making relies on a balance between deliberate and instinctive thinking.

The Tipping Point is the biography of an idea, and the idea is very simple. It is that the best way to understand the emergence of fashion trends, the ebb and flow of crime waves, or, for that matter, the transformation of unknown books into bestsellers, or the rise of teenage smoking, or the phenomena of word of mouth, or any number of the other mysterious changes that mark everyday life is to think of them as epidemics. Ideas and products and messages and behaviors spread just like viruses do.

So the first task of a police force is not to fight crime and enforce the law. It is to establish legitimacy with the law-abiding citizenry and then fight crime and enforce the law.

A study at the University of Utah found that if you ask someone why he is friendly with someone else, he’ll say it is because he and his friend share similar attitudes. But if you actually quiz the two of them on their attitudes, you’ll find out that what they actually share is similar activities. We’re friends with the people we do things with, as much as we are with the people we resemble. We don’t seek out friends, in other words. We associate with the people who occupy the same small, physical spaces that we do.

A lot of what is most beautiful about the world arises from struggle.