When visiting an Iranian household for the first time or on a special occasion it is customary to bring a small gift. Flowers, sweets or pastries are popular gift choices.
Meal times in Iran vary considerably from those in Europe and the US. Lunch can be served from 1:00 – 3:00 p.m. and dinner is often eaten after 9:00 p.m. These and other social occasions in Iran are often long, drawn-out affairs conducted in a relatively relaxed tempo, often involving pastries, fruit and possibly nuts. As it is considered rude to refuse what is served, visitors should accept the items offered, even if they do not intend to consume them.
Source: Atieh Bahar