I have heard do not trust any body:

This was really nonsense! I have read in security things that you should not trust any body, etc. I kept that in mind, I was very aware of my surrounding, (even if I wouldn’t show) but I really saw absolutely nothing with people to feel untrustworthy. I saw such a beautiful simplicity and loyalty with people, who I met. I saw very pretty emotional and human interactions that I have just seen in small villages in Iran, where people are not poisoned with the modern life style. Friendship is build very quickly and people were holding it very strongly, every body wants to help you. The concept of hospitality has an extraordinary meaning here. You are guest, and every thing is for you: time, money, love, respect. I have many examples of everyday, with total strangers in street or shops, or with people who I met. I was really amazed, even with my Iranian identity! Either I have been very lucky, or it is not as bad as it is said. I do realize that because of 30 years of war people have developed a very strong and complex survival attitude and mentality that it is difficult to understand, but it seemed to me that certain values are very strong here.