26 ETIQUETTE RULES EVERY ENGLISH TEACHER IN JAPAN SHOULD KNOW: "In Japan, if you’re on time you’re late. Make sure to arrive to work, class, meetings, and everything at least five minutes beforehand. This doesn’t mean no one can ever be late (you’re human and so are Japanese people). But understand being five minutes late in Japan isn’t 'no big deal.'"
United Kingdom: Class Teacher for Teenagers aged 11-13 years 
http://ift.tt/2tvJYFm there is a school prank in Japan and a couple other countries called "Koncho" where students wait for a comically-opportune time and shove their fingers up their friends butts. Apparently it's a big culture shock for English teachers in Japan when their students randomly Koncho them.