What is that one series, that was either canceled or forced to have a rushed ending, that had the potential to be great but was cut too short to see it and you keep wondering, years later, how good it would have been had the author been able to continue?
Gal Cleaning. It was enjoyable, but nothing special. Then the author found out it was axed after one volume, the author went a little crazy. He created 14 point chapters, that suddenly went dark (from a happy, but dumb romcom to sexual violence and the like out of nowhere). I ended up dropping it before that actually showed up, but it it still haunts my memories.