It is no secret that Director Joss Whedon was not too happy with how Avengers: Age of Ultron turned out when it was released in 2015. Whedon and Marvel even argued over scenes to add, keep and remove during the production.

After the Tribeca Film Festival on April 18, Whedon and Mark Ruffalo, who plays Bruce Banner and his alter-ego Hulk, sat down for an interview and discussed their experience as part of the Avengers films.

During the interview, the director revealed just how badly the production of Age of Ultron affected him. He clarified, however, that the negative feeling he has toward the 2015 film does not only stem from his conflict with Marvel over their creative differences, but also how the output fell short of his self-expectations.

"I think that did a disservice to the movie and the studio and to myself. ... The things about it that are wrong frustrate me enormously, and I had probably more of those than I had on the other movies I made," he said.

Despite the conflict with Marvel, he is still thankful that he was given the opportunity to direct two Avengers films, but he also claims that he will not take the director's seat for any of it again.

Ruffalo said that he asked Whedon to stay for the production of a third and a fourth Avengers film, as well as the third installation for both Hulk and Thor solo films.

"I've been begging him, and he said 'I'll never do it again,'" Ruffalo revealed.

So, what is next for the director who has introduced many amazing cult favorites like Buffy the Vampire Slayer, Firefly, Dr. Horrible's Sing-Along Blog and the currently airing Marvel series Agents of S.H.I.E.L.D.? Well, in November 2015, he revealed that he was working on a musical, but he had apparently put that on hold to write a story for a serious film - and seriously dramatic, for that matter.

"I wrote all the way through to the end of the movie, and I was crying so hard in public. ... I had to take off my shirt and blow my nose into it. I couldn't stand up. I couldn't stop crying," he said. "I just wrote the end of the movie and I'm pretty sure it works."

Everyone out there who did not like how Avengers: Age of Ultron played out, you are not alone. Even the film's director was not satisfied with it.