Anime & Manga

I imagine almost anything with a Gecko Ending fits. Also here should be the series where something happens and they're rushed to finish it in the next 2-3 episodes instead of 10-15 as planned or something on those lines, faintly recall seeing a few like this before. But both of these are special cases, more interesting is when there's no external pressures and there's plenty of material, yet they screw it anyway. Rosario to Vampire comes to mind, the manga had the usual harem and comedy shenanigans, but went full shonen. The anime discarded most if not all of the shonen for the harem/comedy shenanigans and ended funny but less good as a result. Never watched S2 because of this, no idea if there's more. I suspect nearly every case in the thread is behind the scenes a result of executive meddling, but that's just gut feeling.