I just got back from a trip to Australia and it was outstanding. I figured I would have a really tough time with the 14 hour LAX to Sydney plane trip since I had only been on domestic flights previously, but for some reason I found it easier to fly the longer trip. I adjusted much faster on this trip than I have on coast-to-coast US domestic flights. The only thing I can figure out is that maybe it has something to do with the fact that I was able to sleep so much (8 hours) on the plane.
I also had a much easier time with driving on the other side of the road, which I thought would give me fits. It was a little hair-raising when I had to turn right or left the first time, but after that it was no problem.
One of my Australian friends there referred to his country as the "51st state" and it certainly did seem close to the US in a lot of ways, but there were some things that really made it seem like a foreign country. First and foremost was all the Rugby on TV. I thought I was confused after watching it but then asking an Australian about it and having them go into the differences between Rugby League and Rugy Union and Australian Rules Football was even worse. That said, I really think I enjoy watching Rugby more than American Football. It moves very fast and that is good for my short American attention span. Because of this short American attention span I had a much harder time watching Cricket, which is like Baseball, but slower.