Because we're in love with the characters.
That's like trying to find pieces of your former partner in your new partners. It will simply never be the same, and you'll both wind up miserable.
All that aside, it can actually help you get a job in certain industries. I know someone who became a narrative designer for Blizzard who got her start writing fanfiction.
Sigh, if you really love the characters then you need underetand that they exist in an objective context; if you shatter the context you eliminate the character.
"grotesque skinsuit" + "find pieces of your former partner in your new partner" you fellows can't seem imagine a concept called
SIMILARITY
you can isolate those virtues you adored & find a vessel in your own work that can hold them;
it's possible
it's not like you're doing something more than an inventive 'copy'
PS i mean, i already mentioned too that you could write a continuation or substory that doesn't contradict the genuine canon fic if you want the exact unique characters
it could also be mentioned that many fic don't have a legitimate canon art structure: they are more interesting ideas (an interesting concept) than genuine art- so there's not a big obstacle in using the data freely
Lastly | there really exists the possibility that a "parallel world" or a future or past or even simultaneous foreign event that greatly resembles the story can be real ~ but as I said before Free Will makes it so uniqus beings make unique choices -it's not logical eternally mimicking or surely expecting identical outcomes even if you don't alter the events as a 'variable'
