Strangely, that book I was reading recently suggests that this is an idea of personality more popular in East Asian than Western Europe, which may explain some things.

Yeah, if there is Major Traumatic Experience that explains it all, you'd figure that the creator would have mentioned it as important to the conception of the character. Well, all of my favorite characters who angst have something already to angst about. >:D So I don't need to invent some incident.

Exactly. Putting the Suikoden characters in highschool only works if you're writing parody or deliberate badfic. For some reason this is an insanely popular genre, if only because so many of the writers themselves are thinking about what will happen when they go to HS next year. :P