3. Star Wars Episode VI: Return of the Jedi
The Ending: Darth Vader, the vicious antagonist throughout the series, turns against the Emperor to save his son, Luke, and after dying, stands aside ghosts of Obi-Wan and Yoda, having seemingly redeemed himself for his past atrocities. Oh, and there's dancing Ewoks celebrating the Empire's defeat.
Why It's Infuriating: After the brilliant darkness of The Empire Strikes Back, it all seems a bit rushed and haphazard by comparison. The redemption of Vader is sickly sweet, and there's not sufficient build-up for him saving his son, given that the two were trying to slice each other to pieces just moments earlier. Furthermore, it's hard to think of Vader as redeemed given everything horrible we've seen him do throughout the three movies; as a result, placing him next to Obi-Wan and Yoda seems like something of an empty sentiment. And the dancing Ewoks are so, so corny, clearly just part of Lucas' plan to sell more action figures. Though this film gets a lot right, it falls rather short in the denouement.