Knowing how people will use something is essential

We expert teachers know that motivation and emotional impact are what matter.

It was always amusing to be inside Apple and read what journalists said we were doing

Readers always seem to think that the author has some control over the design of their books.

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.

The designer has an obligation to provide an appropriate conceptual model for the way that the device works. It doesn't have to completely accurate but it has to be sufficiently accurate that it will help in both the learning of the operation and also dealing with novel situations.

A challenge to the designers of the world: Make signs unnecessary.