Seeing as how David Benioff and DB Weiss didn't turn up for the panel at San Diego Comic-Con for 'Game of Thrones', you can probably guess their reasons why.
While that panel passed off without any real incident - other than Nikolaj Coster-Waldau defending Jamie Lannister's death (ugh, really?) - the panel after it was definitely controversial.
Seth Rogen, who's an executive producer on 'Preacher', ended up spending quite a bit of time dissecting 'Game of Thrones' and just how poorly it all ended.
"I just wanna say we're following the 'Game of Thrones' panel, which is a f*cking nightmare, just objectively," Rogen began. "I also know that the showrunners didn't turn up, because they didn't want to answer questions about the show... I'm not one of the creators of 'Game of Thrones', I am the creator of other TV shows, so feel free to ask me any 'Game of Thrones' questions you might have throughout the night..." Rogen added, to some nervous laughter from his fellow panel members, including Ruth Negga and Dominic Cooper.
When asked by the moderator which finale would be more satisfying - 'Preacher' or 'Game of Thrones' - Rogen responded by saying, "Well, I'm here at least!"
It didn't stop there, either. Later on in the panel, Rogen segwayed into another jab on 'Game of Thrones', specifically calling out Bran being chosen as the King of Westeros. "I imagine those guys regret making Bran the King because, ultimately, he doesn't have the best story..." Rogen laughed. "(Arya) learned all that face shit, where'd it go?"
Not only that, Rogen responded to an audience question on whether or not it was a mistake not having Jamie kill Cersei in the final season, to which Rogen responded enthusiastically. "I do, honestly! You don't want to follow these people for three years and then have them die in rubble. Anti-climactic."
You can watch the full panel here, with the jabs at 'Game of Thrones' occurring at the 2 minute mark, again at 24 minutes in, and then roughly at 39 minutes in.