Dexter — "Remember the Monsters?" (2013)

Dexter's lumberjack ending is the most bewildering finale on this list, with the protagonist faking his death to live in Oregon isolation. Showtime's investment in a 2021 revival, Dexter: New Blood, spending $30 million to correct this ending, confirms its failure. The original finale's 4.6 IMDb rating underperforms the average of the top 5 worst finales by 1.2 points, driving network intervention.