Tony Xu on why customer obsession sometimes means baking cookies at DoorDash: “When our backs were against the wall, and we had, I think, less than two weeks of cash runway, and we had a terrible night where every single order was late, we made the decision to refund everyone. That cost us over 40% of the bank account. We baked everyone cookies and delivered them at 05:00 AM before everybody woke up. I think it demonstrates that this was a real value. It’s actually my test, really, which is,…