Oh man, I have to totally agree with that, having been to Australia, the UK and even Canada. It helped a bit that when we were in Australia, we were staying with friends, so they were able to help us acclimate, but still...

It's also one of the reasons I love going to grocery stores whenever I'm in another country, because there's quite a bit that's the same on the surface, but the more you look, the more differences you can see (we actually plan trips up across the border to Canada just to stock up on Canadian grocery items a few times a year).

And funny you should mention toilets, because that was the big one that tripped us up when we were in Australia. Being American, we would ask about the restroom or the bathroom... which apparently comes across as a bit stodgy or stuffy to Australians, while toilet to us generally means just the porcelain thing that one would find in a restroom! And after a bit, we started asking for the washroom... which probably just shows how confused our brains were getting (and was probably due in part to our regular Canada trips).

BTW, I found it interesting how many things dr_carrot mentioned that aren't true about other parts of the US... things can vary by region here almost as much as they do by country.