You are three-quarters through a terrible novel. You have already spent eight hours reading it and find it tedious, poorly written, and a waste of your time. Do you keep reading? If you do, you are committing the sunk cost fallacy, allowing past investment that cannot be recovered to distort a decision that should be made solely on the basis of future costs and benefits. The rational response is to put the book down immediately: the eight hours are gone regardless of what you do next, and the only question is whether the remaining hours of reading will be worth...