In a study questioning hotel owners from around the world rated tourists by nationality and, to my surprise, the worst tourists are not Americans but the French!
While the French got props for dressing well to travel, evidently they are even worse than Americans when it comes to speaking local languages where they travel and adapting to local customs. They are often viewed as arrogant because of that, and somewhat tightfisted (since they have different tipping customs in France where the gratuity is included in the bill). Most French vacation in France, preferring that to traveling abroad. Brits and Germans are considered the best international travelers from Europe.
The very best tourists in the world, not surprisingly, are the Japanese.