re: Retailer/server employees: worst ever customer?

I worked at CC's Coffee House in college. One day we lost power and this lady came in wanting a mochasippi. I apologized about not having power and offered her a coffee or tea (on the house). She said she'd take a latte. I apologized again, explaining to her that the espresso machine needed electricity. She eventually settled on an iced tea and bagel. I then watched her for 5 minutes trying to toast her bagel. I didn't have the heart to explain it to her again. To her credit, she was polite about the whole situation.