That hospital that needs a critical next day shipment is saying their life and death shipment for a terminally ill patient should take priority over a couple tropical fish, LOL. Importance is relative and there are many reasons a customer selects the next day air option, in addition to live stock. A business that cannot get a key part can lose thousands per hour without it, taken from experience. That same size box could be destined to Ford carrying microprocessors that just hit the dock in California that they need to restart their Ford F150 production line again. To FedEx I am sure these are what they care more about, just reality.