What's annoying is that many people consider Americans = inhabitants of the USA.
In french there's a precise word, étasunien, in spanish too, estadounidense... in English I guess you can just call them "U.S. People".
I remember I posted a youtube comment a while ago in which I said America wasn't a country and that "Americans" weren't the same as "U.S. people". I got surprising answers (made me laugh, although most of them were filled with hate, people apparently don't know how to express themselves politely nowadays)
This one was WTF
Now there are more important issues than that but :D