Oh, my gosh, there’s so much that could be said on this subject. This would be based on what folks have told me and that which I observed in foreign countries. Also, from what I have observed from foreign visitors in the United States.
First of all, let’s take eating. “American’s eat like pigs,” is an actual comment I heard and another one was: “I had to teach someone how to use a fork,” someone said, referring to the time he spent working in the southern states.
Europeans sit at the table with fork in one hand and knife in another both utensils standing up on the side of the plate, which, to me, looks like animals about to pounce on their food, but I never say any thing about that because they consider it quite mannerly.
On the other hand, American’s are known to switch the fork from one hand to the other. This allows the American to cut the food by holding it down with the fork and cutting with a knife. Then the knife is placed down and the fork is moved to the dominate hand. Something that really irks the European, is when the American uses the side of the fork to slice food into a bite size.
American’s are taught to eat with elbows off the table, the left hand (or right if it’s the dominate hand) on the lap where the napkin has been placed.
American etiquette frowns on using utensils to gesture with. I’ve seen folks in European restaurants waving their forks around to make a point.
My philosophy is when visiting other countries, do what is easiest for you, but don’t make fun of another style of etiquette. This goes for American’s traveling abroad and Europeans visiting America, as well.