10. Why designs go wrong

• Innovation is faster than human evolution /adaptation.
• Aesthetics do not equal usability.
• Designers are not typical users.
• Designers work to please clients, not end-users.
• Design is for every-person; however, we are all special.
• Gulf of Evaluation is too wide (difference between perceived and interpretable physical representation of system and intended actions).
• Gulf of Execution is too wide (difference between user intention and outcome).

Three Teapots [.pdf]