Despite our best efforts, bad or inexplicable decisions are as inevitable as death and taxes and the grocery store running out of your favorite flavor of ice cream. They’re also just as predictable. Why, for instance, are we convinced that “sizing up” at our favorite burger joint is a good idea, even when we’re not that hungry? Why are our phone lists cluttered with numbers we never call? Dan Ariely, behavioral economist, has based his career on figuring out the answers to these questions, and in his bestselling book Predictably Irrational (re-released in expanded form in May 2009), he describes many unorthodox and often downright odd experiments used in the quest to answer this question.