Don Norman
Have you ever pushed a door that was meant to be pulled? Poorly designed objects cause human error, frustration, and confusion in our everyday interactions.
Affordances define the possible physical interactions that exist between a user and an object.
Signifiers provide essential visual or auditory clues that communicate exactly where and how an action should take place.
A strong conceptual model helps users intuitively understand how a system works without needing an instruction manual.