How I Met Your Mother — "Last Forever" (2014)

How I Met Your Mother's finale remains the most divisive in sitcom history, killing the Mother after nine seasons of build-up and sending Ted back to Robin. This twist was so controversial that creators released an alternate ending on DVD, acknowledging widespread betrayal. Compared to Seinfeld's meta-trial ending at #6, which divided 76 million viewers over thematic closure, HIMYM's romance reversal sparked more raw emotion; a 2014 survey of over 10,000 fans showed 45% rated the finale as "terrible" on a 5-point scale. The show's meticulous storytelling—culminating in the Mother's death from illness—left many feeling cheated, with the romantic payoff for Ted and Robin feeling unearned after seasons of character growth.