"In Iran it is common to say no out of politeness when offered something. Only if the other person asks again will you say yes. Actually, you might even say no multiple times.

Cab drivers will do this too for instance. You ask how much you owe them and they’ll say something along the lines of “oh don’t worry it’s worth nothing” to which you then reply by insisting on paying. Only then will they tell you the price and bla bla bla."