Our species, it appears, is hardwired to get things wrong in a staggering variety of ways. Why did recipients of a loan offer accept a higher interest rate when a pretty woman's face was printed on the flyer? Why did one poll on immigration find that the most despised foreigners were from a group that did not exist? Why does giving someone power make them more likely to chew with their mouth open and pick their nose? And why is your sister going out with that biker dude? In fact, our cognitive, logical, and romantic failures may be a fair price to pay for our extraordinary success as a species—they are the necessary cost of our adaptability. Bozo Sapiens swoops effortlessly across neurochemistry, behavioral economics, and evolutionary biology (among other disciplines) to answer with clarity and wit the questions above—and larger ones about what it means to be human.