Snowflakes
The first time he had seen them, he had been a little older than two years old. They had fallen from the sky, gently and silently. They were beautiful. White and soft, yet cold at the same time. Like magic, they turned to water and disappeared in his hand. He had asked what they were, turning to the woman standing beside him. She had smiled, and told him that they were snowflakes. He had asked how they were made, even though his two-year old self couldn't understand much. His mother explained that they were tiny parts of frozen rain, all stuck together in a little ball.
Kakashi had listened, a little confused, but kept on watching the snowflakes fall.
Three years later, he had seen the snowflakes for a second time. But then they had seemed beautiful, now, they were eerie, scaring him a little, reminding him of a sorrow he had just managed to forget. He had fought the tears, reminding himself that shinobi don't cry, even though he himself had just started the academy. The snowflakes had whispered to him, telling him they were proud of him. Kakashi, in slight shock and surprise, had told his father about it. His father had sighed, and said it was his mother talking to him. Kakashi knew that his mother could use ice-type jutsu, and that she had died a few days ago.
Another three years after that, he had seen his father lying dead, a katana thrown to the side. He had stood, in alarm, for what seemed like an eternity, gazing at the body of the fallen White Fang. He had ran outside, only to be confronted by the snowflakes, which fell and made the pain a thousand times worse. They, in their delicate white forms, had fallen, just like his father. They had disappeared, like his father. Kakashi tried and tried with all his might to ignore them, but he found he could not. They were too cold, and too real to ignore.
Another few years later, Kakashi had been on a mission, and had finally made a friend. Tragically, that friend had been taken from him. While saving Kakashi, he had sacrificed himself. As he watched his team-mate lay the white lilies in front of Obito's grave, the snowflakes had once again fallen, mocking him and teasing him. Kakashi had again tried to control the tears, but one escaped, falling to the ground, surprising him, his team-mate, and his sensei. Kakashi never cried, never. But the snowflakes kept coming. The cold and the melting of the snowflakes symbolised death, and as the landed on Kakashi's skin, they reminded him that he was the one who always lived, while his friend and family died.
Kakashi hated snowflakes. He could see the mangled corpse of a loved one, and not cry. He could hear their last few words, and not cry. He could watch them breathe their last breath, and not cry. But he could not see snowflakes, and not cry. Other children loved to see them, on a cold winter's morning, but Kakashi hated them like he hated death. To him, snowflakes symbolised death, an end, the final moments of life.
Snowflakes were the worst thing on the planet, existing to make Kakashi feel guilty.