Your idea of the Japanese male will vary wildly depending on what kind of manga you read. Like the default dream of every boy is becoming a wizard at 30. Large numbers of teenagers live alone because their parents are working overseas. Boys are horny monkeys that will do anything to lose their virginity...except have sex. If they trip, they somehow get a handful of tit.
But, there is one constant in all of manga - Japanese men have absolutely terrible social memories. Childhood promises, anniversaries, birthdays (including their own)...doesn't matter, they can't remember shit.