There is a good reason why famed Avengers: Age of Ultron director Joss Whedon decided not to move on with the next two Avengers films (Infinity War Parts 1 and 2) in the Marvel Cinematic Universe as well as quit his Twitter account following the release of the latest superhero movie: The latest movie simply "broke" him, the director said.

"It's weird because the first one was very, very, very, hard. This one was much harder. It a little bit broke me," he told The LA Times' Hero Complex.

He actually thought that doing the second Avengers film would be easier than the first one, but he was surprised with the work entailed. Whedon admitted that production was "lovely" and the whole cast and crew were supportive of his vision.

"The first time around, my editor Lisa Lassek, Kevin Feige and myself, I think those were the people who knew what I was trying to do," he shared. "Even the actors sometimes were like, 'We have no idea what he's doing, but he seems to want to do it very badly, so we're going to go with it.' And God bless 'em, they were very trusting, even before. And then they saw, and they were like, 'Oh, that's how that works.'"

Despite the overwhelming support Whedon got from everybody, his own creative genius got the better of him. The director wanted Avengers: Age of Ultron to be its own movie, and beat the success of the first one. He worked harder on the script, and shot it very differently.

Whenever he told himself, "I want to make something great," a voice inside his head would nag at him, "But is this a great idea?" After completing a scene, he would feel happy with what they have accomplished but then the nagging voice inside his head would say again, "I don't know Joss, could you have done better? You could have done better."

Whedon suffered from self-doubt, and because of this, the studio did too. Given the hype surrounding the movie, all of those working on it felt immeasurable pressure. "Everything's riding on this all of a sudden. And it became a problem in a way that nothing else has. And it was a hard movie to make on top of that. So being paralyzed by either indecision or the weight of responsibility? Not useful, don't have time for your paralysis, son, snap out of it. This was the hardest work I've ever done," he said.