Ariely begins by discussing the concepts of relativity. The notion that humans are not inherently good at rationalising their value, or in economic terms, utility, "we focus on relative advantage and estimate the value accordingly." This idea is quite controversial; some believe we are hardwired to be irrational, whereas others contend that rationality can be trained. The essence of Ariely's message is that, despite what stance you take, the irrational choices we do end up making have patterns and, thus, are predictable.

Interestingly, throughout the book, Ariely routinely conducts experiences with scholars from MIT, which seem to fall for all these tactics, which suggests it is probably impossible to eliminate irrationality completely. Nevertheless, Ariely argues that being aware of the ways in which we behave irrationally may help us behave less irrationally. l