[danenania]

Part of it is that many Americans really are obnoxious as tourists and with a big population that can afford to travel we are sending a lot of those obnoxious people around the world.

If you make some effort to learn the basics of the language and blend in to the existing vibe rather than acting like you're on spring break in Daytona Beach, mostly people will realize you're not one of those Americans and you won't have any problem.

[chihuahua]

This is a good point. I bet it's much more that locals are tired of obnoxious tourists, and not tourists in general or tourists from any particular country.