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.
In Naruto's sad childhood fanfiction, his experiences at the academy could be a focus. He was constantly the outcast there too. Other kids were afraid of him or made fun of him. Fanfic writers could show how this affected his self - esteem and his determination to prove himself, which later becomes a driving force in his journey to become Hokage.