Why backstories are so interesting to characters and wish they were canon.

So I was to some audio production videos that were fan made and as I was listening to them I sometimes get to feel that they were more interesting than the shows would do or filling in backstories to the main character or other characters since the main show and plot of the episodes does sometimes. 

Well yes Audio production are from fans of the shows that want to give more depths to the characters' backstory and where they were before coming to the main location where the character(s) are in. Since we have seen Fan fiction stories on the internet and YouTube that are interesting then what the main one from the creators give us but lack to give out more background information if better than the one that can sometimes have production issues from the cast and crew but sometimes i wish if any interesting stories can be canon to the main story but we have to create our own canon stories.