I'm a proud member of the Starbucks army. I find myself procuring their fine beverages pretty much every day of the week.
Starbucks has this pretty crude but normally effective "requirements" policy where drink order specifications are written right on the cup into which the libation will be prepared and served.
Now I'm not one of those riffraffs that consumes my coffee cocktails out of plastic or paper vessels -- I provide my own thermos (Starbucks branded, of course). They even give me a discount for using it. That's just how I roll.
However, my eccentricities come at a cost. Starbucks is wise enough to not scrawl my order on the side of my thermos, and thus the barista is left to his or her own wits to remember my order... and they get it wrong... every... single... time...