On the rare occasion I order at Starbucks (I like a local place called Dutch Bros, it's pretty popular in my neck of the woods) I order a medium. When they try and correct me with "Ok, so that's a venti caramel mocha" or whatever, I cock my head to the side, look at them blankly, then say, "No thanks, just a medium."
I enjoy watching the look on their faces as they struggle with the decision on whether to 'educate' me, express disgust at my ignorance, some combination of the two, or finally to just acknowledge that a venti or tall or whatever is actually just a 'Medium'.
