For example, if I have to referee a game with a Polish team playing against a Mexican team, I have to understand that the two teams will play differently and therefore make different mistakes. Most European teams adopted a playing style where they kick around their feet whereas Mexicans do not. Because Mexicans use more of their upper body, other players may think that creates more opportunity for violations. Those kinds of observations have to impact my judgment on violations. A good referee knows these things and uses that knowledge to make appropriate calls.
Soccer fans can be vicious and they can be great.
They are certainly unlike any other sports fan in the world. Soccer fans , especially internationally, act very different from football fans. They tend to be more rowdy abroad than within the states, which means the international matches I referee tend to be more interesting. I was once pelted with plastic glasses. For the most part, I have not had any bad incidents.