When Hatake Kakashi was a child, he refused to cry.
Crying, he taught himself, was a sign of weakness. Good ninja never cried, and what more could he ever want out of life than to be a good ninja? Of course, he also wanted his father to pick him up and throw him onto his stolid shoulders, his eyes shining with unspokenpride as he laughed richly, dancing about and spinning in circles until they were both dizzy enough to vomit, but he was sure that that would all come soon after he became a good ninja.
When Kakashi had come home one day after struggling for hours on end to become a good ninja, he found his father. More specifically, he found his father's still-warm corpse, blood leaking sluggishly from the exposed arteries that were hanging limply from his severed head. Kakashi hadn't cried then. He had looked bleakly at his father's body, shock widening his eyes and whitening his tightly clenched fists, but he had not cried. He had felt that that would be like spitting on his father's remains.
It would be some time later, just long enough for some of the gashes that had scored his mind to close up, before Obito, the foolish black sheep of the Uchiha clan, would look at him with rage and disbelief clouding his gaze. It would be at that time that the 'crybaby', as Kakashi always called him, would say the very thing he himself had been unable to ('I believe that the White Fang was a true hero!'), ripping open the gashes far too quickly, making them bleed heavily, so heavily that his eyes nearly watered, but he didn't cry. He couldn't.
A few hours later, his teammate lay dead, crushed by a rock and Kakashi's foolishness, one of his eye-sockets empty. It was then that Kakashi cried, for Sakumo and Obito and his own stupidity, for knowing that good ninjas didn't cry, but being ignorant to the fact that great ones did. It was then that Kakashi cried, but not with his own eyes.