I for one work as a sandwich artist and we saw that comic strip a while ago and have done that since then. I have also gotten WHAT! YOUR OUT OF AMERICAN CHEESE!! HOW CAN YOU MAKE A SUB WITHOUT AMERICAN CHEESE?!?! Then I'd calmly explain how there is other cheese and in the end they'd throw the receipt at me. Quite sadly you get used to all the complaining so much you really are as calm as the artist in this animation.