The memorable "Soup Nazi" character from "Seinfeld" was made memorable by his intolerance of the slightest delay or uncertainty in placing one's order at his diner. A dismissive "No soup for you" was all he needed to dispatch with a laggard.
Of course, that was before customers started queuing up at cash registers with cell phones attached to their ears. Today, proprietors of coffee shops and eateries are turning to signage more than service denial to combat the rudeness of the not-ready-to-order crowed. Here are some examples of the genre.