From an interview in Newsweek with Steve Jobs:
What was the design lesson of the iPod?
Look at the design of a lot of consumer products—they’re really complicated surfaces. We tried make something much more holistic and simple. When you first start off trying to solve a problem, the first solutions you come up with are very complex, and most people stop there. But if you keep going, and live with the problem and peel more layers of the onion off, you can oftentimes arrive at some very elegant and simple solutions. Most people just don’t put in the time or energy to get there. We believe that customers are smart, and want objects which are well thought through.
Every time I have to use Windows, I realize it can get the job done, but it seems so poorly thought out. I know he’s talking about the iPod in this question (and I don’t own one), but I feel this process of thought has gone into the design, features, questions, and UI of Mac hardware and the OS. Linux is a nice idea, but doesn’t yet have the thought behind it to make it marketable.