Creator Breakdown: Of a sort. Closed his Twitter account three days after the release of Avengers: Age of Ultron. After it was speculated that his departure resulted from criticisms regarding the film, particularly the controversies regarding the Bruce/Natasha ship and Natasha angsting over her infertility, Whedon denied that he left because of the backlash, but because he wanted to go to a "quiet place":
Whedon: I just thought, Wait a minute, if Im going to start writing again, I have to go to the quiet place. And [Twitter] is the least quiet place Ive ever been in my life.
Creator Couple: With Kai Cole who produced many of his works until they divorced.
Creator's Pest: Whedon has mentioned in interviews that he's not a fan of The Punisher, viewing the character's concept as fascistic and irresponsible. During his time writing Runaways, Whedon brought in the Punisher for a guest spot, and intentionally wrote him in an extremely unflattering manner.
The unaired Buffy pilot. It's on Youtube if anyone's interested. Also, the film.
IGNFF: Is the presentation ever going to make it to DVD? Whedon: Not while there is strength in these bones. IGNFF: Well, I mean, it's one of the most heavily bootlegged things on the Internet. Whedon: Yeah. It sucks on ass. IGNFF: Yeah, it does, but it's sort of that archival, historical perspective... Whedon: Yeah, I've got your historical perspective.
Carlos Jacott, best known for shooting Bill Henrickson in the finale of Big Love, played the smarmy villain Ken in the Buffy episode "Anne". He would later appear on Angel ("Bachelor Party") and Firefly ("Serenity").
He trolled the Avengers fanbase by killing off Quicksilver, and later with the final scene in Avengers: Age of Ultron. In the former case, Quicksilver lampshades his own death with his movie catchphrase "Didn't see that coming." In the latter case, when Captain America welcomes the Avengers' newest surviving recruits, he triumphantly says "Avengers, a-" right before getting cut off by the end credits. Prior to the film's release, Joss had confirmed that the movie was "one minute shorter" than the first installment.
According to Disney animator Tom Sito, Whedon did some uncredited script doctoring for The Little Mermaid.
As mentioned under Old Shame above, he's done some uncredited script edits that turned out so poor, he prefers they be unknown. Those works technically qualify, but without knowing what they are, they can't be listed here.
A particularly potent one, for comic books fans and companies alike: before he was attached to The Avengers, Whedon was writing a Wonder Woman movie for DC Comics. DC passed on it, he got the Avengers job from Kevin Feige, and the rest is history. Whedon ultimately cast the actress he claimed to have had in mind to play Wonder Woman, Cobie Smulders, as S.H.I.E.L.D. agent Maria Hill, and she did get to play the character eventually in The LEGO Movie. However, after the release of the 2017 Wonder Woman film, his script came under fire for being perceived by some as sexist - focussing far more on Steve than Diana, while giving creepily loving descriptions of her beauty in lieu of giving her a particularly interesting personality. When asked about the script at the Avengers: Infinity War premiere, Whedon defended it, saying its easy to take one phrase out of context. He went on to point out that the portrayal of female action heroes in film has advanced drastically since he had written the script; not that I was the most woke individual... ten years ago, but I was in there swinging and... the characters have integrity and I stand by it.