1. Michael Bay - Transformers: Revenge of the Fallen
Well, you have to hand it to Michael Bay. Even he can admit when he's made some mistakes. In an interview back in 2011, before the third Transformers film Transformers: Dark of the Moon was to be released, Bay admitted the problems with his second film in the franchise, Transformers: Revenge of the Fallen (2009):
"We made some mistakes. The real fault with is that it ran into a mystical world. When I look back at it, that was crap. The writers strike was coming hard and fast. It was just terrible to do a movie where youve got to have a story in three weeks. I was prepping a movie for months where I only had 14 pages of some idea of what the movie was. Its a BS way to make a movie, do you know what Im saying?"
Of course, Transformers: Dark of the Moon wasn't that well received either, but at least he's honest about the mistakes he makes.