In the startup world, we mostly hear about the success stories. To a startup, "be like Netflix" is pretty hard if you're not Reed Hastings in the late nineties. What's really valuable, however, is tales of honest failure. But founders are reluctant to bare their souls and admit where they were wrong. Fortunately for you, we're pretty convincing. With the caution, "do as I say, not as I do," these founders will reveal their greatest gaffes—if only to serve as a cautionary tale to others.