Pretty much the entirety of the Animorphs book series, but I guess there was a reason for it. But for some kids books, holy hell.

"See, win or lose, right or wrong, the memory of violence sits inside your head. It sits there, like some lump you can't quite swallow. It sits there, a black hole that darkens hope, and eats away at everyday happiness like a cancer. It's the shadow you take into your own heart and try to live with."