According to a recent international survey, the French are now considered the most obnoxious tourists from European nations, and behind only Indians and the last-place Chinese as the worst among all countries worldwide.
I guess that just adds to the stereotype of the French being rude. I've never been to France, and I don't know enough French people to know how much truth there is to the stereotype.
But this doesn't surprise me:
Americans "demand the same exceptional service they are used to at home, which is why they rank as the loudest, most inclined to complain, and among the least polite."
Especially if they're part of The Amazing Race. I like that show, but as Americans are running across a city, screaming at cab drivers and throwing fits when things don't work out, the "Ugly American" gets cemented in people's minds.