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 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.

To me, error analysis is the sweet spot for improvement.

Simplification is as much in the mind as it is in the device.

If you're more susceptible to interruption, you do more out of the box thinking.

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 electronics industries—it's not your fault. Don't blame yourself: blame the designer.

The world is complex, and so too must be the activities that we perform. But that doesn't mean that we must live in continual frustration. No. The whole point of human-centered design is to tame complexity, to turn what would appear to be a complicated tool into one that fits the task, that is understandable, usable, enjoyable.