I've been to Asia, Europe and North America in that order!
As a Chinese person who was born and raised in Australia, going back to my parent's hometown in South China is extremely different in terms of the culture and lifestyle I have in Australia. Living in Australia I was lucky that I was raised in a way where I still remained very much connected to my Chinese culture - in fact, students in our primary school were made to learn Mandarin which was something that I found interesting. However in China the atmosphere itself is completely different - for instance even though most of my high school is composed of Asian students (90% +) and extremely academic-focused, the academic life in China from what I have heard and witnessed being in China is much more intensive. There are a lot higher expectations of children there and you can see it in their work ethic, and discipline which is beyond anything I have seen in other countries. Furthermore there is a lot of censorship in China - I remember when I first went back and being shocked at how much of the internet is censored and how much the Chinese government tries to restrict certain information. I had always wondered why my Dad seemed so uptight and against people saying anything against the Chinese government, but the threat of being prosecuted is an extremely real threat. It made the atmosphere quite uncomfortable at times. Other than that China is also extremely overpopulated and polluted - furthermore, whilst the cuisine is great (maybe I'm a bit biased) - you also have to be careful when it comes to areas such as street food as it can be unreliable or not properly made. It was definitely a very different experience. Also the traffic there was out of this world - we managed to cross a six lane highway because there was a huge traffic jam for kilometres where you only moved about 1km in an entire hour. It was wild. Despite all this though, it was still an enjoyable experience in other aspects (seeing Chinese history, the cuisine etc.) is amazing.
However not to generalise Asia as a whole like China - in fact, other Asian countries are very different. I've been to Japan also and it was vastly different from China - whilst it still had that same overcrowded, urbanized feel - it also felt much more comfortable and safe of an atmosphere. It also felt a lot more clean, at least if you were some distance away from the major cities. They also had bullet trains which I didn't notice in China that much. Overall though Asia is extremely different from other continents in terms of areas such as cuisine and also general lifestyle and beliefs.
As for Europe and North America, I don't know if there's any extreme differences from Australia but they did feel different in a sense! In Europe I guess I just noticed how different all the architecture was, if that's anything notable? Europe has a much longer history, and since Australia is a super young nation it definitely felt very different in Europe - there were so many historical landmarks to see that were fascinating and tourist attractions like castles etc. which you never see here. North America was different in the sense that there are some different expectations - like tipping service staff which I don't think gets done in Australia very often? The people there are a lot more friendly and willing to chat as well where it's rare to see strangers just initiate random conversation here. Also we got to meet some other high school students from America and I guess one thing I noticed is how much more emphasis they put into extracurricular activities - things like homecoming, football games etc. which we don't have here and their spirit for their school clubs are next level compared to here! But yeah those are some things I have noticed in general as differences I guess. :)
