Rational thinking is an important aspect of human nature, but we have imagination, we have ambition, we have irrational fear, we are swayed by other people, we get indoctrinated and we get influenced by advertising.
Ha-Joon ChangSelf-interest, to be sure, is one of the most important, but we have many other motives - honesty, self-respect, altruism, love, sympathy, faith, sense of duty, solidarity, loyalty, public-spiritedness, patriotism, and so on - that are sometimes even more important than self-seeking as the driver of our behaviors.
Ha-Joon Chang