Con man William Penn Patrick understood the basics of relieving people of their money: 1. people want to believe there's an easy way to get rich, and 2. when they realize they've been conned they are often too embarrassed to admit it. Patrick's three most notorious businesses, launched between 1963 and 1974, were lucrative but also unethical and dangerous.
Holiday Magic purportedly sold cosmetics, but that was just the gimmick. It was a pyramid scheme, in which every participant's income depended on recruiting others, even after their initial investment. Spectrum Air repaired planes, with deadly results. And Patrick's Leadership Dynamics Institute was an expensive course in self-improvement that involved torture to toughen participants up. The activities included lying in coffins, being semi-crucified, whipping, kicking, humiliation, eating bad food, and even worse. Eventually the FTC and other in investigative bodies caught up with him. Read the story of William Penn Patrick and his scams at Mental Floss.