A friend of mine ran a men’s underwear and t-shirt company for a while. To build a full profile of the customer, they needed to know exactly how many t-shirts and pairs of underwear their typical customer had, and in what condition. He asked them, and they obliged by telling him. But t-shirts and underwear were not the sort of things his customers monitored closely, so getting good feedback required a different approach. Somehow, my friend convinced his customers to let him a