Better to take up a huge order to the check stand greet the clerk with a cherry “Merry Christmas” and if the clerk won’t or can’t reply in kind, walk away.
Even the dullest of managers will get the message as they have visible in-your-face evidence of lost sales, and they have to reallocate scarce personnel to restock the shelves with your cart’s contents.
cherry should be cheery.
I think it’s time to eat...