Good design imposes constraints on the user so that, in that scene, only one single correct thing appears possible. The designer must understand and make use of every kind of natural constraint.
Use the power of natural and artificial constraints well.
Error is unavoidable in everyday life.
Design is about using the power of constraints, using forcing functions, or making the consequences of actions visible. Then we no longer have to suffer confusion or pain from errors that are not caught.
Book: from The Design of Everyday Things
