When people describe the best way to develop technology products it often sounds a lot like the scientific method: hypothesis, test, learn. This is a great place to start; when done well, and fast, it goes a long way to solving problems that users actually care about. But, intelligence and brute logic can only get you so far when your success depends on the behavior of real live human beings. The difference between promising and legendary depends on intuition, creativity, and taste. The best technology companies in the world find ways to balance these forces.