My wife recently got me watching Avatar: The Last Airbender and thus far it's excellent. However, I know the live action movie is supposed to be trash (though I still plan on watching it so I can fully grasp the hate it receives).
Made me wonder about other films/shows that screwed the pooch despite having really good source material. I would say GoT, but it was great until they ran out of source material. The Hobbit trilogy comes to mind, but it also had some decent moments too.
What are some other examples?