From our smartphones to our bicycles, the user experience provided by manufactured products has an enormous impact on our lives. Down to the smallest details, designers often puzzle over how to best align a product with the demands of the customer. But that wasn’t always the approach, and Cliff Kuang, author of User Friendly: How the Hidden Rules of Design Are Changing the Way We Live, Work, and Play, explains how this revolution of design has taken hold and dramatically changed our patterns of consumption and use.