User-centered design means working with your users all throughout the project.

In the university, professors make up artificial problems. In the real world, the problems do not come in nice, neat packages. They have to be discovered.

The designer shouldn't think of a simple dichotomy between errors and correct behavior; rather, the entire interaction should be treated as a cooperative endeavor between person and machine, one in which misconceptions can arise on either side.

User experience is really the whole totality. Opening the package good example. It's the total experience that matters. And that starts from when you first hear about a product experience is more based upon memory than reality. If your memory of the product is wonderful, you will excuse all sorts of incidental things.

In my opinion, no single design is apt to be optimal for everyone.

Everything has a personality: everything sends an emotional signal. Even where this was not the intention of the designer, the people who view the website infer personalities and experience emotions. Bad websites have horrible personalities and instill horrid emotional states in their users, usually unwittingly. We need to design things-products, websites, services-to convey whatever personality and emotions are desired.

It is relatively easy to design for the perfect cases, when everything goes right, or when all the information required is available in proper format