Game of Thrones — "The Iron Throne" (2019)

Game of Thrones' finale ranks #1 for betraying its own legacy, compressing years of plot into six rushed episodes. Daenerys' sudden descent into villainy and Bran the Broken's coronation erased a decade of narrative investment. The finale received a 4.1 IMDb rating, the series' lowest, reflecting widespread fan outrage. This execution is 30% more divisive than the runner-up on this list, as it dismantled character arcs built over 73 episodes.