LOL, guys, the truth is that "sense of humor" is not always universal. A large part of it is "regional" humor (not to mention "insider" jokes, running inside small groups), which will be always most appealing to the group (like nation etc.) where it was born. This is because such groups of people share experiences that may be not known elsewhere. Another problem are the jokes which rely solely on "playing with the language itself" and these can rarely be translated. And we can also say that some nations are more "fun loving" (e.g. France), while other are more serious (e.g. Finland).
The jokes from certain country may be more "international" than those from another. Thats why other nations create opinions that "country A jokes are cool, but those from country B suck". This is not necessarily based on who is your "traditional enemy or ally" - I can confirm from my experience that I love jokes from a certain country, which is ... err... not a natural friend of my country