How do you know if something is wrong with your culture? Horowitz to three indicators: bad people leave too often, you don’t meet your top priorities, and an employee does something that really affects you. This led Ben Horowitz to ask how to create and sustain the culture you want. He turned to three historical figures and one contemporary who were “extremely effective in getting the culture they wanted.” “He was not so much interested in the culture they were producing as in what they had to do to change themselves and their culture. They said culture is the most important thing because it determines how a company makes decisions when you’re not around. Shaka Senghor, the American ex-con who founded the most impressive prison gang in the yard and ultimately changed prison culture. The samurai who ruled Japan for seven hundred years and shaped modern Japanese culture. Make sure your culture fits both your personality and your strategy. Think carefully about your weaknesses because you don’t want to program them into your culture. The best way to get a sense of your culture is not what managers tell you, but how new employees behave. Culture is not the sum of your demeanors, but a series of actions. Bring in a former employee from the culture you are targeting. One of the most common and destructive mistakes leaders make is to assume that people will “do the right thing” even if it conflicts with other goals. Any rule that is so amazing that people ask, “Why do we have this rule?” will reinforce important cultural elements. People learn more about what it takes to succeed in their organization on day one than any other day. Companies like gangs, armies, and nations are large organizations that rise and fall based on the daily microbehavior of the people in them. Toussaint Louverture, the Haitian slave who led the only slave rebellion in human history. Don’t let your first impressions be wrong or arbitrary.