I just read this very sad but true post by by Kate Sedgwick over at Traveler's Notebook titled: How To Avoid Being an Ugly American Tourist. (Thanks for the link Lola!)

Fair enough, there are obnoxious tourists from everywhere on earth, but the article states some darn good examples of ugly tourist behavior that are commonly associated with American travelers.
I especially like Lesson #3: "Be humble. Your country sucks, too."