Customer: “Excuse me, I sent a letter last week but it came back. Can you tell me why?”

Me: “Sure, do you have it with you?”

(The customer hands it over. It doesn’t take long to figure out the problem.)

Me: “Oh, okay. You’re going to need a valid house address to have it sent.”

Customer: “I did put the address!”

Me: “That’s an email address, ma’am.”

Customer: “Yes, and it’s valid. I checked!”