I had the opportunity to watch it for the first time on DVD and it had commentary and all, so I could tell that everybody there was just having fun with the source material…but… Ella Enchanted. The original book wasn't exactly "literature destined to be a film instead of a movie", but I expected better than a live action wannabe-Shrek.
The Avalon High adaptation made no sense. It wasn't that King Arthur couldn't be reincarnated into a girl, it's that there was no buildup to that because that wasn't the twist in the book. Why wasn't Jennifer cheating on Allie with Lance, then?? They just didn't think that their target audience would know (or care to find out) who the Lady of Shalott was.
While the casting, the costumes, and cinematography were appropriate, I actually didn't like the Stardust adaptation. Victoria in the movie was too much of a stereotypical mean girl, and that wasn't the case at all in the book. Plenty of people like the pirate subplot, and I guess that was a generally positive message (of, yeah, it's totally all right to let dudes loudly and misogynistically disrespect you if you know that they're working through image issues and identity issues—no), but I also thought it lacked subtlety and dimension. It's a serious issue that they didn't take seriously in a movie that didn't take anything seriously. It was awfully performative.
The movie version of His Dark Materials actually got Nicole Kidman cast in it when that part was written for her…but, eh, too much shiny trying-too-hard-to-be-epic CGI. I'm glad they did a miniseries remake, but then again, I haven't watched the miniseries remake. I've heard they changed some things so that Asriel isn't as morally ambiguous, which would be disappointing.