One common theme could be loneliness. Naruto often felt alone during his childhood, and at Christmas, this feeling might be intensified. Another theme could be sacrifice. Characters might sacrifice their own Christmas cheer for the greater good of the village. And also, the theme of unfulfilled wishes, as not all characters can have their ideal Christmas due to the harsh shinobi world they live in.
Maybe it includes the names of his lost friends. Since Naruto has lost many important people in his life, their names on the Christmas list could represent his longing for them during the holiday season.
His unfulfilled dreams could also contribute. Naruto has big dreams for the ninja world and for himself. If in the fanfiction some of these dreams are still out of reach, they could be on his Christmas list in a sad way. For instance, if he dreams of a world where all ninjas are truly equal but that hasn't happened yet, it would be a sad entry on his list during Christmas.
Naruto himself is likely to be the focus. His difficult childhood and his longing for family make him a prime candidate. Sasuke could also be a focus, as his quest for revenge often led him to be alone and Christmas could be a time when his isolation is highlighted. Hinata might be another, as her unrequited love for Naruto could lead to some sad Christmas scenarios."
"Answer2": "Definitely Naruto. He has always been an outcast in the village for a long time, and Christmas could be a time when he feels that even more. Sakura could be in the spotlight too. Maybe she misses Sasuke during Christmas and it makes her sad. And Kakashi, with his past traumas and the fact that he has lost so many people, his loneliness during Christmas can be a great focus in such fanfictions.
A Naruto fanfiction can be sad when it delves into the sacrifices Naruto has to make. He gives up so much of his personal life and relationships for the sake of the village and his friends. If a story highlights how he loses his close friends, like Sasuke in some darker interpretations, it can be extremely sad. Additionally, if it shows Naruto being misunderstood by the people he's trying to protect, that also adds a layer of sadness. For instance, if the villagers still don't trust him despite all his efforts, it can be a very tragic situation for Naruto.
One aspect of Naruto's sad childhood in fanfiction could be his loneliness. He was shunned by the villagers because of the Nine - Tails inside him. In many fanfictions, authors explore how he coped with this isolation, like finding solace in small acts of kindness from a few people, such as Iruka - sensei.
Unfulfilled dreams can also be a theme. Naruto has always dreamed of becoming Hokage to gain the respect and recognition of the village. If in a fanfiction, something prevents him from achieving this dream, like an unexpected injury or a political conspiracy, he would be extremely sad. He has put so much effort and hope into this dream, and to see it slip away would be a huge blow to him.
There was a couple, Jack and Rose. They had been together for a few years. Christmas was always their favorite time. But this year, Jack lost his job. He became withdrawn and moody. Rose tried her best to cheer him up, but he pushed her away. As Christmas approached, the pressure of not being able to afford gifts and the stress of his situation made him snap at Rose one too many times. On Christmas Eve, Rose couldn't take it anymore and left. Jack was left alone, surrounded by the twinkling lights that once symbolized their love, now only a reminder of what he had lost.
In a small town, an old man named Mr. Thompson lived alone. He used to love Christmas when his wife was alive. They would decorate their house together and invite neighbors over. After she passed away, Christmas became a sad time for him. One Christmas, he put up a small tree but couldn't bring himself to decorate it. He sat in his dark living room all day, thinking of the past, while the rest of the town was bustling with Christmas cheer.