for me kakashi did he had to grow up with out knowing the touch of his mom he lost his dad to depression can you imagine that seeing the only person you have change from a father to cold and lost soul then coming home to him dead on the floor and after years of being on your own you finally meet new loved ones then have them die off
Obito: he felt like his death was on his hand's because he was stuck on the rules and didn't accept his friendship when he first offed it
Rin:he made I promise to his dying friend to take care of her and he had to choose between killing his friend or save the village in the end he had to kill her
Minato:was his teacher and maybe like a father or big brother to him that was the last of the people he had close to him
his teenage years: he had the same nightmare of killing Rin and he was in anbu there's no telling what kinda sick and sad things he had to do and see
So to me kakashi
Obito: he felt like his death was on his hand's because he was stuck on the rules and didn't accept his friendship when he first offed it
Rin:he made I promise to his dying friend to take care of her and he had to choose between killing his friend or save the village in the end he had to kill her
Minato:was his teacher and maybe like a father or big brother to him that was the last of the people he had close to him
his teenage years: he had the same nightmare of killing Rin and he was in anbu there's no telling what kinda sick and sad things he had to do and see
So to me kakashi