Double Espresso

Just had one of those coffee shop experiences that drive me crazy.

barista: Hello! What would you like today?
me: Double Espresso please.
batista: Ah, what exactly do you mean by a double espresso.

I mean really? What is hard about this?

And then, just to highlight how uncoffee they are, the smallest ceramic mug is a 12 oz. coffee cup. Oh the humanity of it all. :-)