As another Canadian on the boards, I have only this to say regarding travel abroad:

Be polite. Say please when you ask for something. Say thank you when you get it. Say thank you if you get something you didn't ask for. When you bump into someone, say "I'm sorry," and mean it. When someone bumps into you, say "I'm sorry," and mean it. Hold doors open for people, especially older people or those with disabilities. Be genuinely nice to everyone around you, and people will not see you as an American, they will see you as a nice person. Energy works when you're sarging; try to stay low-key when you're abroad. It's a different SPAM, like day game. You don't bring nightclub energy to a bookstore. You bring bookstore energy + 1.

And that goes for everyone, not just Americans. Canadians have been getting themselves a reputation lately for being rude and arrogant when we're abroad. That is because we ARE rude and arrogant when we're abroad. We seem to figure that, since everyone liked us after the second World War, everyone should still like us now. What has Canada done for Norway recently? Not a whole lot. When was the last time a Canadian died to liberate France? A long time ago.

No matter what country you are from, when you are travelling abroad try to be the best representative of your country you can be. You are not just there as yourself; everyone you speak to, everyone who notices the flag on your backpack, will associate your behavior with thier opinion of your nation of origin. So make sure you make a good impression. Eh?