A lot of countries like to crack a joke or two at the expense of the U.S. That is, until someone else invades them (unless America is the one doing the invading). Americans don't really mind this sort of thing, as I've observed that a great deal of it spawns from jealousy.
Americans however, have a skill at the dinner table that is unrivaled in any country. It's not how many hotdogs they can eat (a sore topic now thanks to the Japanese). It isn't how their medium pizza is considered to be bigger than a large in any other country. It isn't even how they accept, nay, ENCOURAGE the idea of free refills.
It's how they use their forks.
When it comes to utensils, nobody can rival the Americans in the use of a single fork to eat an entire meal. Got some meat on your plate? Many will eat it as if the knife never existed. It's pretty hard to eat peas with just a fork isn't it? Well not for the Yanks. You could even give them a bowl of melted ice cream and they will STILL somehow manage to finish it using only a fork. You name it, and the average American can gracefully eat it with only a fork in the right hand.
I always get funny looks when I ask for a knife. This isn't some attempt to show how cultured I am compared to my hosts. It's just that I'm simply incapable of using only the fork. It's the exact same feeling you get when you ask for a knife and fork at an Asian restaurant when everyone else is using chopsticks. While I may technically be one of America's newest citizens, I'm afraid I can never be truly American until I have mastered this skill (and start liking John Wayne, fat chance).
I suspect that somehow this is a deeply rooted rebellion against the British, since they hold their forks with the left hand. These days the Americans are rather blase about it, and it's almost maddening. They don't acknowledge it as a skill, it's just how they eat. My advice for anyone visiting the States is to resist the almost uncontrollable urge to correct them, and just marvel at the symphony of dining before your eyes.