[quote=@gowia]
Characters who are 'Grizzly war veterans who have "seen things, man!" ' 
[/quote]

Conversely, I've seen far too many characters who either witnessed, did, or suffered through something that many of us would consider horrible, and it has absolutely no effect on them until they aren't the center of attention.

Tragedies don't have to be a character's central focus (and probably shouldn't be the only thing about a character), but, if they left no impact, then they're just another card to play when the game of misery poker begins.