Funny, &quot;na merci&quot; is basically the same as &quot;non merci&quot; in French - since the words are so similar I wonder if that expression does not come from French somehow.<p>Other than that, the whole process is not unique to Persians. Maybe they are extreme about it, but in Japan you can see pretty much the same kind of situations as the ones they described... while I must admit the taxi driver telling you the trip was &quot;nothing at all&quot; is rather amusing and unique.