Predictably Irrational: The Hidden Forces That Shape Our Decisions author: Dan Ariely rating: ASIN or ISBN-10: 006135323X binding: Hardcover list price: $25.95 USD amazon price: $24.10 USD

"Why'd they do that?" -- a familiar refrain. Why do people engage in sometimes irrational behavior?

This is an excellent survey of the forces influencing the way people act. The author examines the effect of social norms, money, sexual arousal and more.

Why do people behave the way they do when faced with certain choices? Thought provoking and enlightening, worth reading again. I've added this book to my all-time favorites list.

Oh, and the author, Dan Ariely, maintains a blog on his web site.