I once owned a very popular food shop, and I always loved telling people to knock off the vapes. Now and then, someone would try to look tough in front of their buddies, and try to argue with me, and only succeeded in getting them, and their buddies, kicked out.

I would tell them: "This shop is my kingdom, and I'm the Emperor, and what I say goes, PERIOD. Do what I say, or get out!" I would say it exactly like that, while glaring into their eyes. Few ever argued a word after that, and those that did, were tossed out, FOREVER.