Japan is probably the most polite country in the world. One way of showing it is using honorifics after somebody's name.
-san: The most common honorific, it is used as Mr, Mrs, Ms, etc. Mostly used when politeness is required
-sama: Higher then san, used to show great respect
-dono: Even higher then sama, probably used for gods, emperors, presidents etc.
-chan: Mostly used among girls (but also for boys), sometimes used to express affection.
-sempai: Used to address upper-class people
-kohai: Used to address lower-class people
-sensei: Used for teachers and mentors
-blank: You don't havta use honorifics when you're good friends with a person.
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