What are the biggest mistakes people make when visiting Iran?
Being impolite and too gready, especially western tourists!
Iranians are famous worldwide, for being one of the most hospitable people, and it's becoming quite a popular tourist destination, just look.
This has to do with many things, including Irans history, geography and nature. However more and more tourist also travel to Iran, to meet it's people. The tourist have may have heard about how they would get invited into the homes of the natives, getting free food etc. Iranians are, largely, warm and hospitable people, but that doesn't mean that foreigners should abuse this. A lot of people (mostly westerners) abuse the politeness, to such a degree, that they even refuse to pay, for instance, a local tourist guide. I've heard many stories about this, and it's getting more and more common, for tourists to travel to Iran with $20 in their pocket, and still expecting a place to eat and sleep in. The don't even book a hotel, because they are expecting to be invited in to others' homes.
Also I truly hate when western tourist travel to Iran and bring a superiority complex with them, seeming to look down upon Iranians viewing them as inferior.
If you are planning to visit Iran, learn about the country's history and, most of all, show gratitude towards your hosts (if you are getting invited into a local's home). Is it really so bad to leave a small gift or a present for your host, who has provided you with delicious meals and a home?
Using credit cards while they are traveling in Iran.
This may happen mostly when traveler is going to stay in 5 Star hotels and they think it's possible to use credit cards. Although political sanctions partially lifted, but it's not possible yet.
Even exchange shops in the Ferdosi St., can accept credit cards. The only place that you can cash out from your credit card is www.persiatravelmart.com.
This travel agency charge your card and pay you Iranian Rial immediately.
Calling Iranians Arab.
I remember back in 2007 when there was an American tourist who came to Tabriz. We had a little talk and I just wanted to impress him with my fluency in English. Then he turned around after a few seconds. He aksed one of my friends that how despite being Arab we still have problems with Saudi Arabia. Aren't at the end all of Iranians descended from Arabs?
Oh boy, the whole thing got so messed up that he apologized for his ignorance. :D
Recording Video near to military and security stations.
Based on Iran regulation, you can not shoot in public area however it seems while you're a tourist so don't be a problem for you or give you a notice by police to turn your camera off. It's fine until here but Recording video or taking picture from military buildings, police stations, security organization is forbidden and you will be arrested and ask you to explain why you shoot.
So don't try take picture and video when you saw police, army or etc.