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.

Complexity is acceptable as long as it is intelligible and necessary. We want to avoid needless complications.

The hardest part of design ... is keeping features out.

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

Beauty and brains, pleasure and usability - they should go hand in hand.

Rule of thumb: if you think something is clever and sophisticated beware-it is probably self-indulgence.

Design is really an act of communication, which means having a deep understanding of the person with whom the designer is communicating.