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

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.

Having the best product means nothing if the people won't buy it.

How do you discover a need that nobody yet knows about? This is where the product breakthroughs come through.

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

In design it is important to shoe the effect of an action. ... Feedback is critical.

Products were once designed for the functions they performed. But when all companies can make products that perform their functions equally well, the distinctive advantage goes to those who provide pleasure and enjoyment while maintaining the power. If functions are equated with cognition, pleasure is equated with emotion; today we want products that appeal to both cognition and emotion.