Vengeance leads eventually to more conflict and drama and death. Especially because it started after a mistake/misunderstanding. GoT fans already know this; see Rhaegar and Lyanna. But also, this series shows us the drama/tragedy/responsibility of being special. To some you're a freak, to others you're a superhero. It's a burden you must carry. Well...GoT fans know this also. I'm not gonna say who, 'cause it's obvious.