Not Always Right

This game is based off an existing website.
I know a lot of people on this site work in retail, food services or in tech support or simply in jobs where you deal with idiots and now is a chance to tell the stories about the customers who make your days seem like years or trips into the sanitarium.

Example ( this actually happened to me):

(A pair of customers, I assume husband and wife, approach my cash register, note: I work in retail, ugh!)

Me: Hi, did you find everything you were looking for?

Customer#1(male): Yeah, thanks

Me: Would you like to sign up for our rewards card? It gives you all sale prices on any item on sale

Customer#2(female): So we can't get the sale without the card?

Me: No, I'm sorry

Customer#2: I hate this store and stores that do stuff like that!

Me:*quiet, unsure of what to say other than sorry*

Customer#1: Calm down, it's not his fault


It's your turn now, any dumb, strange, annoying or stubborn customers you've dealt with? Or have you simply been witness to a customer like that while being in a store,restaurant or any other place?
Go ahead and let it out!