10 Exact Moments That Killed TV Shows

4. The Mother Dies - How I Met Your Mother

How I Met Your Mother was an undeniably revolutionary sitcom, albeit one which eventually crumbled under the weight of its own convoluted, long-form storytelling.

The final episode of the series' eighth season finally revealed The Mother aka Tracy (Cristin Milioti) to audiences, seemingly setting up a ninth season which would place an affecting capper on how she and Ted (Josh Radnor) became a couple.

Except, the season nine finale derailed all that promise with the shock reveal that Tracy died of a terminal illness in 2024, and in 2030 - the time where older Ted is relaying the entire story to his teenage children - his kids suggest he still has feelings for their "Aunt" Robin (Cobie Smulders), and encourage him to ask her out.

The "it was really Robin all along" reveal left a sour taste in the mouths of most fans, undoing seasons of character development and shifting the goalposts regarding the show's entire premise.

Sadly, the ending re-colours the show enough that it's honestly tough to re-visit earlier episodes with that knowledge in mind.

Though a superior alternate ending was eventually released - in which Tracy survives, Ted stays with her and Robin stays with Barney (Neil Patrick Harris) - the canon ending is what will stick in most fans' minds.