Customers are people. They lead lives. They have kids, they eat too much, they don’t sleep well, they phone in sick, they get bored, they watch too much reality TV. If you’re building for some kind of idealized, economically rational buyer, you’ll fail. But if you know your customers, warts and all, and you build things that naturally fit into their lives, they’ll love you.

— Lean Analytics, A. Croll & B. Yoskovitz