The human mind is exquisitely tailored to make sense of the world. Give it the slightest clue and off it goes, providing explanation, rationalization, understanding. … Well-designed objects are easy to interpret and understand. They contain visible clues to their operation. Poorly designed objects can be difficult or frustrating to use. They provide no clues–or sometimes false clues. They trap the user and thwart the normal process of interpretation and understanding.