(The customer rips the lid off of the shake I just hand her and frowns.)

Customer: “What is this?”

Me: “That’s a vanilla shake.”

Customer: “No it isn’t. I want a vanilla shake.”

Me: “Well, I made it myself so I promise you it’s vanilla. Would you like me to remake it?”

Customer: “No, I just want a vanilla shake! This doesn’t look like vanilla at all. It’s all yellow.”

Me: “Ah, the vanilla syrup gives the shake a yellow tinge. It’s
supposed to look like that.”

Customer: “Oh, it’s not ME you have to convince, it’s the seven year-old in the car. He won’t be happy!”