It may seem that the customs rules are changing on a minute by minute basis. But patience and an even temperament will go a long way to help you through the process. It also helps to remember that the laws are different in many places and you might find it necessary to do something you would never dream of doing in the States just to get your gear off the dock and into the theatre. Check with as many local authorities as you can before you do anything, however. There are things we do here that would be illegal in some other places.
Local customs can be different and confusing.
Check it out before you go. In Arabic countries, for example, you never point at anyone. It's considered very impolite. And while belching may be considered polite in some countries, France is not one of them. For me one of the most fun aspects of travel is new food.