I don't know what's number but:
Memorist - too many plot twists, when they revealed a big villain, I was like "did you have to complicate things this much?" I cannot say it was very disappointing but I kinda got tired
Zombie Detective - big villain was out of place and whole reveal felt extra and abrupt
Watashitachi wa Douka Shiteiru - all episodes except last were great and beautiful, then in last 40 minutes the drama turned into theatre of absurdity including wtf big reveal