Why do our headaches persist after we take a one-cent aspirin but disappear when we 

take a fifty-cent aspirin? Why do we splurge on a lavish meal but cut coupons to save 

twenty-five cents on a can of soup?
 
When it comes to making decisions in our lives, we think we're making smart, rational 

choices. But are we?
 
In this newly revised and expanded edition of the groundbreaking New York Times 

bestseller, Dan Ariely refutes the common assumption that we behave in fundamentally 

rational ways. From drinking coffee to losing weight, from buying a car to choosing a 

romantic partner, we consistently overpay, underestimate, and procrastinate. Yet 

these misguided behaviors are neither random nor senseless. They're systematic and 

predictableΓÇömaking us predictably irrational.