6. "A New World, Part Four: Finale" (season 9, episode 13)
Ugh. I wish it didn't come to this. I really, really wish it didn't come to this.
To say that fans were disappointed with the series finale of The Flash would be an understatement. The whole final season was a huge misfire, designed only to irritate the loyal fans who watched to the end and it completely overlooked the legacy of this phenomenal show. And yet, when its final storyline kicked off with a sensational episode, there was hope. Hope that had long evaporated by the end of the season.
The crux of "A New World, Part Four: Finale" is pretty solid. It's an all out war between Team Flash and the avatar of the Negative Speed Force, Cobalt Blue. It brought back some beloved faces from the show's decade-long run and featured the long-awaited birth of Nora West-Allen. And yet, the execution let it all down.
The fact that the show's final ever storyline had just four episodes to tell its story was the major issue here, as the series finale felt rushed. Moreover, it became all about Barry and a new enemy and overlooked the long-standing rivalry between him and archenemy the Reverse-Flash, who was defeated by Allegra (yes, Allegra). Oh yeah, and Cecile - an empath - can now inexplicably fly.
Personally, I felt that the finale was an adequate end to an inadequate season, but that wasn't enough to make up for how underwhelming it was. The last five minutes of it are beautiful, though, and if the overall episode was of the same standard as that final scene, it wouldn't be on this list. But unfortunately, the creative team continued to ignore fans' requests for a final season that actually cared for its characters, and just proceeded on like it was any old season.