South Korea's viral fake shopping apps let users endlessly browse menus and checkout without spending money—the dopamine hit of shopping without the purchase. Sam Parr and Shaan Puri explore this trend, then dive into Nick Sleep's "shared economies of scale" investing philosophy that turned billions into multi-billion-dollar positions by measuring how much surplus companies pass to customers. They also cover Lloyd Blankfein's billionaire frugality, David Rubenstein's second-act collecting empire, and Nat Turner's brilliant $400M PSA card-grading business—a credence-goods trust layer that captures entire industries. Nick Sleep's core investing insight is identifying companies that maximize "shared economies of scale"—passing surplus savings to customers instead of raising prices, which builds loyalty and market dominance.