George Lucas well, there were a lot of Star Wars fans that turned on him when the prequels came out. I was there. He became a punchline. Though that seems to had decreased a tad bit after the sequel trilogy came out.
James Cameron, I'm not really sure. I know he has a draconian approach to directing his movies;like pinning actors' phones to the wall with a nail-gun. But I don't know if he's been embroiled in anything serious.