Variations on an old rant.
You have no idea how to construct a decent sentence and really don’t care.
You can not or will not use sensible formatting, and stick your readers with a mass of run-together text and/or other discourteous and inhospitable barriers to comfortable reading.
You misspell characters’ names. Really, this stuff is in print, it’s in a book, you can look it up. This is supposed to be fanfic, for cryin’ out loud, it’s all about the characters.
You don’t have a story, just an “idea”, and it’s never going anywhere. You will either peter out after a dozen posts or natter on into infinite boredom.
You believe what your readers say about your great story and your great writing…and because of that, you will never get any better.
Most of this could be recycled under the title: Why I Won’t Beta Read Your (Unfinished) Novel.