The final chapter discusses quitting and why it’s so hard for people. We’ve been conditioned to believe that failure is bad and makes one a loser. However, as the authors write, “There is in fact a huge upside to quitting when done right, and we suggest you give it a try” (190).

First, they discuss why people don’t quit, beginning with the stigma involved. A negative view of failure is ingrained in our culture, so we learn early on that quitting is bad. They quote a 1941 speech Winston Churchill gave at his old boarding school, in which he exhorted the boys to never give up no matter how small the stakes, to illustrate this conventional view of quitting.

Second, there is the idea of sunk costs. People reason that when they’ve already invested a certain amount of time, energy, or money into something, they must see it through to completion. Finally, people don’t think enough about opportunity costs, which are the costs (time, energy, money) involved in not doing something else while you’re occupied with a failing endeavor.

Levitt and Dubner admit that they quit about nine out of every 10 of their projects. They see failure as an important form of feedback and tell the story of a company that actually celebrates it.