“For example, for most of our loyal repeat customers, we do surprise upgrades to overnight shipping, even though we only promise them standard ground shipping when they choose the free shipping option. In conjunction with that, we run our warehouse 24/7, which actually isn’t the most efficient way to run a warehouse. The most efficient way to run a warehouse is to let the orders pile up, so that when a warehouse worker needs to walk around the warehouse to pick the orders, the picking density is higher, so the picker has less of a distance to walk. But we’re not trying to maximize for picking efficiency. We’re trying to maximize the customer experience, which in the e-commerce business is defined in part by getting orders out to our customers as quickly as possible. The combination of a 24/7 warehouse, surprise upgrades to overnight shipping, and having our warehouse located just fifteen”