Re;creators.

This isn't a case of late entries, seasons or episodes not being as good as the early ones, or a slow decline in quality. This is a series where knowing what happens in the endgame stretch actively ruins the first 17 episodes. This is because the first two thirds of the show are either buildup (to a really disappointing payoff later on) or character drama (which is meaningless as almost all characters then get poor treatment and become aggressively irrelevant at best).

Tl;dr version: it's a series that's really convincing at promising you a great finale and then delivers an incredibly crappy one.