We've had three big ideas at Amazon that we've stuck with for 18 years, and they're the reason we're successful: Put the customer first. Invent. And be patient.
I strongly believe that missionaries make better products. They care more. For a missionary, it's not just about the business. There has to be a business, and the business has to make sense, but that's not why you do it. You do it because you have something meaningful that motivates you.