I work at a local chain of coffee shops in New Orleans. Our drink sizes are "small," "medium," and "large." However, as one might expect, a significant number of customers, used to their Starbucks, order using the Starbucks sizes. This confused me for a while, as I'd only been to Starbucks a few times and was unfamiliar with their size scheme.
Luckily, one of my roommates is a Starbucks barrista (or "partner" or whatever), so I sat him down and had him lay out the counterintuitive meanings of "Tall," "Grande" and "Venti."
The next day: a revelation! Most Starbucks customers have no idea what the Starbucks sizes mean!
"I'd like a Tall dark roast."
--I bring them a small dark roast.--
"No! I wanted a Tall. A big one."
How does Starbucks not explode from all the confusion?