“Solve the surface first The surface is important. It’s where your product or service meets customers. Human beings are complex and fickle, so it’s impossible to predict how they’ll react to a brand-new solution. When our new ideas fail, it’s usually because we were overconfident about how well customers would understand and how much they would care. Get that surface right, and you can work backward to figure out the underlying systems or technology. Focusing on the surface allows you to move fast and answer big questions before you commit to execution, which is why any challenge, no matter how large, can benefit from a sprint.”