A UPS driver told me that UPS has big sorting warehouses with conveyer belts up to twenty-five feet off the ground. If something gets jammed up, packages start pouring off the sides. Shoop, shoop shoop... whistling sound, whistling sound, whistling sound... WHAM WHAM WHAM.Fed Ex Ground for instance has no such high-tech sorting warehouses, so they don't have the opportunity to drop things quite as hard.
Guess which company I don't use.
Duke