There is nothing irrational about love; indeed, without our passions and our principles, where would the motivation come from to make rational choices about anything? So a world explained by economists is not a world lacking love, hate, or any other emotion. (...) If you’ve read some of the criticisms of economics, you may be starting to fear that you're reading a book about an infamous character by the name of Homo economicus, or "economic man." He's the caricature of what economists are generally supposed to assume about people. Homo economicus doesn't understand human emotions like love, friendship, or charity, or even envy, hate, or anger-only selfishness and greed. He knows his own mind, never makes mistakes, and has unlimited willpower. And he's capable of performing impossibly complex financial calculations instantaneously and infallibly. Homo economicus is the kind of guy who would strangle his own grandmother for a dollar - assuming it didn't take more than a dollar's worth of time, of course.