Really? They do that? See, I'd be all like "you know what Barista lady? You serve coffee. You are a cofffffeeeeee serrrrrverrrrrrr. I want a large, and I want it now. I don't care if you call it Satan, just serve me my damn coffee and shut up."
No, I'd never really do that (I've worked in similiar industry and if anything am overly nice) but I find it hilarious there is so much pretention in the world of chain coffee shops.