Bloomberg Opinion columnist Barry Ritholtz interviews Scott Galloway, a professor of marketing at the NYU Stern School of Business and author of "The Four: The Hidden DNA of Amazon, Apple, Facebook and Google." Galloway is also the founder of several firms, including the business intelligence company L2 and the global brand-strategy consultancy Prophet. His latest book is "The Algebra of Happiness: Notes on the Pursuit of Success, Love and Meaning."