"When in Rome, do as the Romans do” I think most people have heard this old saying. Of course, the meaning is that it is the way people follow a land customs and culture there.
This proverb is said in Japanese as well. “Go ni ittewa Go ni shitagae(郷に入っては郷に従え)” Go(郷) means hometown. If I translate this directly, I would say “when in hometown, follow the town”
When you in a different country like Japan which has unique culture and customs, you may have trouble to adjust it. However, it is the best way to follow the way of the land to melt into the place.