When you have trouble with things—whether it's figuring out whether to push or pull a door or the arbitrary vagaries of the modern computer and elect… - Donald Norman

The principle of visibility is violated over and over again in everyday things. In numerous designs crucial parts are carefully hidden away. Handles on cabinets distract from some design aesthetics, and so they are deliberately made invisible or left out. The cracks that signify the existence of a door can also distract from the pure lines of the design, so these significant cues are also minimized or eliminated. The result can be a smooth expanse of gleaming material, with no sign of doors or drawers, let alone of how those doors and drawers might be operated.

Serious accidents are frequently blamed on "human error." Yet careful analysis of such situations shows that the design or installation of the equipment has contributed significantly to the problems. The design team or installers did not pay sufficient attention to the needs of those who would be using the equipment, so confusion or error was almost unavoidable.

"It probably won a prize" is a disparaging remark in this book. Why? Because prizes tend to be given for some aspects of design, to the neglect of all others—usually including usability.