That's the essence of the US Olympic Committee's advice to the American athletes who will compete at this summer's games in Athens.
To be honest, I'm not a big fan of the lack of humility that a lot of athletes exhibit, but often that's down to the nature of the sport. You're more apt to see "strutting" by the winner of the 100m dash than the winner of an archery gold regardless of what country wins.
So, if the USOC wants American athletes to just be a little more humble, fine. But, if I were an athlete and they asked me to tone it down simply because it might provoke anti-Americanism, I'd tell them to go to hell.