[...] Why work with a group of people who don’t even like each other? Many seem to think it’s a sacrifice necessary for making money. But taking a merely professional view of the workplace, in which free agents check in and out on a transactional basis, is worse than cold: it’s not even rational. Since time is your most valuable asset, it’s odd to spend it working with people who don’t envision any long-term future together. If you can’t count durable relationships among the fruits of your time at work, you haven’t invested your time well—even in purely financial terms. From the start, I wanted PayPal to be tightly knit instead of transactional. I thought stronger relationships would make us not just happier and better at work but also more successful in our careers even beyond PayPal. So we set out to hire people who would actually enjoy working together. They had to be talented, but even more than that they had to be excited about working specifically with us. That was the start of the PayPal Mafia.
Excerpt from Zero To One: Notes on Startups, or How to Build the Future by Peter Thiel