Misunderstanding Free Trade

Customer: “I want a cup of 2% milk with four pumps of chocolate in it.”

Me: “What size would you like?”

Customer: “The size that’s free.”

Me: *thinking I misheard, or maybe she’s joking* “I’m sorry, what?”

Customer: “Whatever size is free! I want that size!”

Me: “Um, we don’t have a ‘free cup of chocolate milk’ in any size.”

Customer: “Don’t lie to me! I know that’s why you have the milk out on the condiment bar! But I want 2%, not creamer!”

Me: “That’s for customers to put in their coffee. It’s not so you can make free cups of chocolate milk.”

(It took me almost 10 minutes to convince her I wasn’t going to make her a free cup of chocolate milk.)