One of the Iranians customs:

Being polite is considered as a part of the Persian culture. Tarrof has deep roots in the Iranian custom of treating politely. It is a cultural custom that consists of refusing something which has been offered to you even though you want it.

According to it, if you are offered s.th, like a tea or sweet, even if you want it, at first you decline it until the offerer persists and the insistence becomes greater . So,this tradition encompasses different levels until the fellow ultimately accepts the offer or may refuse it .As an example when you want to buy s.th. and ask for the price; the shopkeeper will inevitably, out of politeness, refuse to quote a price and say it is worth

nothing. However,in reality, he would like to be paid and is just being humble.

A host is obliged to offer anything a guest may want, and a guest is equally obliged to refuse it. This ritual may repeat several times before the host and guest finally determine whether the host's offer and the guest's refusal are real or simply polite.

In some occasions,when you offer s.th,you may ask the addresser not to t'aarof, but that request raises new difficulties, since the demand itself might be a type of t'aarof.