When something is too different or is not understandable to the viewer. Maybe if fan art, too out of the ordinary to be what you're suppose to be drawing. It's called a 'style' and just because something maybe fan art doesn't mean it has to look exactly like the actual thing. But still leave some identification of who the character,etc is suppose to be.
That's how some people get negaitive scoring and do not even mention some people who does art. At least ther're trying. No one pities them but bashes them which is really wrong with negative scoring haven. Sorry for the long reply but that's my opinion. X3