Watch the video Don Norman: Thoughtful Design
Which shaker did you think is the one with salt? The one with one hole or many holes?
"It doesn't matter what you think. What matters is what the person who filled them thinks."
This simple statement describes the essence of user-centered design beautifully.
Here is a more elaborated quote from Usability First.
“Too often, systems are designed with a focus on business goals, fancy features, and the technological capabilities of hardware or software tools. All of these approaches to system design omit the most important part of the process – the end user. User-Centered Design (UCD) is the process of designing a tool, such as a website’s or application’s user interface, from the perspective of how it will be understood and used by a human user. Rather than requiring users to adapt their attitudes and behaviors in order to learn and use a system, a system can be designed to support its intended users’ existing beliefs, attitudes, and behaviors as they relate to the tasks that the system is being designed to support. The result of employing UCD to a system design is a product that offers a more efficient, satisfying, and user-friendly experience for the user, which is likely to increase sales and customer loyalty.”