Ghost of a flea

You may quarrel with an Austrian and argue about God or the world with him, if you like, but if you sit together at a Heurigen (a restaurant serving local wines and local food), enjoying a glass of Gumpoldskirchner Riesling, and you call an Austrian an "idiot", you should remember to add a "Herr Direktor" or "Herr Minister" afterwards - and a polite and nearly untranslatable phrase of 19th century's German may be enclosed called "mit Verlaub", meaning indeed that rhetorically you ask for the addressed person's permission for insulting him. Besides, "mit Verlaub" can also be applied to certain and delicate situations, for instance if you snatch away a seat from a person in a crowded train (in this case it normally is not recommended to greet explicitly, just nodding might do).