If Abbott and Costello ran Starbucks....
It's always special when you can witness someone's first time at Starbucks:
Barista: Here's your tall latte, sir.
Customer: Oh, that's not mine. I ordered a small.
Barista: Tall IS small, sir.
Customer: Tall is small?
Barista: Yes, tall is small.
Customer: Tall is small. Hmmm. Why on Earth would you use tall for small?
Barista: [Long explanation of Tall, Grande, and Venti origins.]