Jeff Lewis, a real-estate investor who buys and sells residential property in swanky Los Angeles neighborhoods, is preoccupied with order, symmetry, perfection, cleanliness, rules, and lists. If his refrigerator isn't stocked with bottles of Evian water, all with labels facing outwards, "there is hell to pay." But rather than tormenting the 37-year-old Lewis—star of the Bravo reality show Flipping Out—these obsessions have turned him into a multimillionaire. In Lewis's line of work, attention to detail is essential. Before putting a home back on the market, he must supervise months of painstaking renovations, typically at a cost of several hundred thousand dollars. "OK, I have a mental affliction," he says. "But it's an asset. My perfectionism sets my product apart."