What are some adaptations with huge disparities in quality between the source and the anime?
This question straddles all three of anime, manga, and light novels, so I figured I'd just drop it in the anime community first. Though if it doesn't belong here, feel free to delete it and I'll go somewhere else.
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I've only been watching anime for a few years. This year, I've started reading manga and LN of some anime I've seen. There are a few titles where I feel like the anime adaptation was just as good and there are some where I feel like it was better. Fortunately, I haven't encountered any cases where I think the anime completely dropped the ball, but I know there probably are some like that.
What are some titles that have huge disparities in quality between its anime adaptation and the source?
The Way of the Househusband's anime adaptation was more of a voice-acted slideshow than an anime.
The Mob Psycho 100 manga's writing was excellent but the art was merely passable. Studio Bones took that simple artstyle and went absolutely nuts with it, turning it into one of the most beautifully-animated works I've ever seen.