In Iran it is very rude to blow your nose in front of everyone, especially with a loud sound, for example it's impolite to do it in class or at a table.
When I just arrived in Switzerland, i was in school. One day, in class, somebody blew their nose rather loudly. I giggle, because I found it funny, but everybody noticed me and i just looked stupid. then i had to explain that in iran, you just don't do that :-D
Soroush is Iranian and lives now in Switzerland.
