I hated how Batman Beyond ended, it had a pitiful finale in "Unmasked" and they could have use it to a much better use then what they did use it for. Terry wouldn't seriously unmask himself so carelessly to one scared kid when there's so many people near and ear to him (hello hot girlfriend DANA) deserve the truth more.
However, I am thankful they gave Beyond a proper ending thanks to both the phenominal Return of the Joker movie, and the episode "Epilogue" in Justice League unlimited. I also think Teen Titans had a very piss poor finale. It seemed pointless for me to bring back Terra when all it did was raise questions that will never be answered and just didn't really accomplish any kind of point.
Titans should have left the series end the episode BEFORE "Things Change", with "Titans together". Now THAT episode screamed finale. An army of super villains, and super heroes battling it all out in a battle royale with cameos, old characters, and new ones galore, that is a proper way to end a series people.
Not bringing back supposed fan favored characters (
never saw what was so great about Terra anyway) and leaving a mile long list of unanswered questions. Strangely enough, I also liked the ending to Mystery Science Theater 3000. I know it was a weird ending but to me, it seemed to fit, it's funny/ironic to think that first chance they get on Earth: they do the same thing they did so many years in space.
Watch bad movies and rip on em every chance they can get.