Here is a list of random experiences people have had with americans:
'god man, I never knew south korea was so much smaller than north korea!!!'
as the seppo points to tasmania vs australia.
'Hitchiking in the US a couple yrs ago and a guy asked where I was from. I replied, Australia and he said: 'damn, must be cool to be able to drive across your whole country in an hour or so' I laughed and said, 'nah mate not Austria, Australia' and he said, 'yeah I know, capital is Sydney, little island at the bottom of the map'
Couldn't believe it when I said it takes about 6 hrs to fly across the country. 'But it looks so small on the map''
Once, on a lift in Aspen, we got talking with an American couple. It was a freezing cold day and we commented on how it had been near 100 degrees (you have to translate or they don't understand) when we left Aus. The woman had this look of puzzlement on her face for a while, then the fog cleared and she said 'Oh, so it must be July down there now!'
at whistler out one night and trying to tune this American. Anyway she asked where i was from (accent) and i go Australia. Her reply was 'gees, your speak such good English for an Australian'.
We were staying with friends in Spokane (eastern part of Washington State) a few years ago. Our daughter was about 18 months old and speaking reasonably well. The husband asked me, referring to my daughter's aussie accent, 'do you have to train them special to talk like that?'
Dead serious, he would not accept that children all over the world didn't pop out of mum with a natural American accent from day one. He was utterly convinced that we somehow had to teach our kids to talk 'different'.
I can't remember which American TV network had the rights to the Sydney Olympics but they were disappointed with the time difference between Sydney and the US. They demanded that it should be the last time the Olympics be held in the 'Southern Hemisphere'.
They must think that somehow China, which is the Northern Hemisphere won't cause the same problems.
According so some I spoke to there is no american accent! everyone else has accents, not them. They didn't believe you when you said that the minute they opened their pie-hole anywhere in the world, people would know they were American.
Some of my friends had an american visiting their house recently, somehow the american brought up the topic of america's founding fathers. When everyone at the table asked who are those guys?
This american couldnt handle it she went on and on about why dont they teach you this in school? How come you guys dont know your american history. Friends said we don't even care who ours were as if we give a rats on who yours were. Apparently this upset the mood at dinner
I was at Adelaide domestic airport and these Americans were waiting for a flight and the lady goes to her husband 'I want to buy a coke (from the vending machine). They're $2, do you think that means they're two american dollars or two of their dollars?'   It was very hard not to laugh or turn around and say something. They really do think that the world revolves around them!
They still can't comprehend that NOONE IN THE WORLD does thanksgiving but them. They are convinced it's a world wide celebrations. Not kidding. If you are talking to or emailing a yank at that time, they'll wish you Happy Thanksgiving.
When I was in Alta one time this guy came up to me, pointed at my Jackson Hole hat (oops) and asked which place was better. I didn't want to offend him any and said JH was better for this, and Alta better for that. He interrupted me, and told me he wanted a 'straight answer to a straight question.' I told him I liked Jackson because the people were nicer, and the mountain gnarlier.
Later that day I caught a lift with a guy who asked me if I was from Alabama (or something like that). I said I was from Australia. He said I spoke good English, and asked me where I learnt. I asked him if he wondered why english wasn't called american (I was having a bad day with insular americans).
On a lift in Fernie we were chatting with a couple of Americans. They asked the inevitable 'Where are you from?' - when we said Australia one of them said 'That's a long way to come to ski - but I guess you can't ski there, hey?' We said we certainly did ski in Australia and the same guy said 'Really? You have snow in Australia?' His mate was better informed though - he said 'Sure they do - they're right next to Switzerland'. You gotta love it. 
... and so on. You'd think the Olympics might have educated them just a bit...