Had a customer try to order his very normal drink by ordering a completely different drink plus the modifications that convert that to what he really wanted. I told him what his drink was called and charged him for that instead of ringing up the more expensive combination of things he described. (Please use a third the word count and save 10 cents.) Had another customer I just had to say no, you can't have that (they eventually picked a real thing that exists and is even on the menu).