" Principles of design:
1. Use both knowledge in the world and knowledge in the head.
2. Simplify the structure of tasks.
3. Make things visible: bridge gulfs between Execution and Evaluation.
4. Get the mappings right.
5. Exploit the power of constraints.
6. Design for error.
7. When all else fails, standardize. "

― Donald A. Norman , The Design of Everyday Things