The Kano model, developed by Noriaki Kano, a Japanese professor of quality management in the 1980s, categorizes product features based on how they affect customer satisfaction. It assumes customers have different expectations and preferences for different features, and not all features are equal. The model identifies five types of features: must-be features that are necessary but not sufficient to satisfy customers, one-dimensional features that have a linear relationship with satisfaction, attractive features that increase satisfaction when present, indifferent features that have no impact on satisfaction, and reverse features that decrease satisfaction when present. For example, a car must have brakes and a steering wheel (must-be), its speed and fuel efficiency are one-dimensional, a sunroof or heated seats are attractive, its color or shape of the dashboard are indifferent, and loud noise or high maintenance cost are reverse.