Each ethnic group has its traditions, habits, etc., better to know them, otherwise it can lead to embarrassing or even disastrous situations.
In Asia (but not only), it is often considered impolite to enter a house with your shoes.
In the Arab world, shaking the hand of someone with your left hand is not polite at all (supposed to be used to wipe your a... only).
etc.
For Japan, do you have something to add, from personal experiences or something you just heard of (including in the language) ?
-www.tofugu.com/2012/09/10/7-things-you-should-do-in-japan-but-not-in-america/
In Asia (but not only), it is often considered impolite to enter a house with your shoes.
In the Arab world, shaking the hand of someone with your left hand is not polite at all (supposed to be used to wipe your a... only).
etc.
For Japan, do you have something to add, from personal experiences or something you just heard of (including in the language) ?
-www.tofugu.com/2012/09/10/7-things-you-should-do-in-japan-but-not-in-america/