Okay so, the reason I dislike this dynamic so much is because when people do this, they turn the entire thing all about them. And they completely mischaracterize the main character, and they change the entire story up. And just make it into some weird ass romance ... I'm only fine with this if you don't change up the story and you don't do any mischaracterization, but when you're just changing up the entire thing, it's just your own oc lore at this point and not even apart of the fandom since it's completely different. Only similar thing related is that you're using the characters, but the characters aren't the characters cause you turned them into something they're not

yeah but then again I'll get called a fun police for saying this but wait till mfs have their favorite main character be shipped with a Mary sue.