From Joel Spolsky’s article User Interface Design for Programmers:

- A user interface is well-designed when the program behaves exactly how the user thought it would.
- Don’t provide options unless the user really wants to choose
- Use real-world metaphors
- Affordances
- Consistency with existing standards (good or bad)
- Users don’t read manuals
- Users don’t read anything (make text concise)
- Users can’t control the mouse very well (large click targets)
- Users can’t remember anything