No company has a culture; every company is a culture. A startup is a team of people on a mission, and a good culture is just what that looks like on the inside. The first team that I built has become known in Silicon Valley as the “PayPal Mafia” because so many of my former colleagues, including Elon Musk, Reid Hoffman, and David Sacks, have gone on to help each other start and invest in successful tech companies.