(We were giving away free packages of instant coffee for promotional reasons. Each package was about the size of a sugar packet.)
Customer: "What’s that?"
Me: "It’s a free package of instant coffee. Would you like one?"
Customer: "How does it work?"
Me: "Just put it in a cup, and mix it with water."
Customer: "Is the cup, and water inside the package?"
Customer’s Mother: "You’re a moron."