Coming to Japan I had to get used to not tipping, not worrying about plurals, and not accidentally misreading the buttons in the toilet stall and calling the emergency help instead of flushing the toilet. I also had to get used to the unending patience of the Japanese to accommodate my confusions and accept my transgressions.
In going to America, a Japanese person will have to learn to tip in myriad situations in which it is just understood that you do so, they will have to learn what items can be pluralized and how to do it, and they will be bored with the button possibilities in the toilet stall. No sounds, no heated seats, no water streams to clean you more fully. And they will likely at some point have to deal with an impatient American speaking to them loudly.
I think I have the easier of the two exchanges. I also don't have to learn to use the word, "the." I had no idea how strange a word this was. When can it be omitted? When must it be used? Being an English speaker, it comes fairly naturally. I've inherited (the) intuition in my ears. But if you never had such a word, it would be so difficult to understand (the) situations where it was needed, or appropriate, or natural, and where not. Imagine a world where things were never singular or plural and never had articles. A free-floating poetic world, where rules were friendly and easy to follow (once you learned them), and people bowed to say hello. This is Japan. Land of (the) Friendly People with no "the."