Disappointment sometimes seems the natural state of mind for science-fiction fans, but it's because we have so much hope. We raise our hopes again and again, only to suffer crushing disappointment. Here are the 10 worst letdowns of the 2000s.

Note: I'm not including the Star Wars prequels here, because the big letdown was The Phantom Menace in 1999. After that, the other two movies couldn't really be letdowns.

The Dark Knight Strikes Again. This was the moment we realized Frank Miller wasn't really Frank Miller any more. He agreed to do the long-awaited sequel to his most famous and groundbreaking graphic novels, the story that redefined Batman for a generation — and he turned in a bland caricature of his earlier brilliance. You can complain all you want about the assitude of All-Star Batman And Robin and The Spirit, but TDKSA was the start of the hackery. Worst moment: When the Joker turns out to be the much-abused Dick Grayson, and Bats kills him without a second thought.

Fox's Reign Of Terror. Firefly should have been one of the great success stories of the 2000s. It's hard to remember now how invincible Joss Whedon seemed going into Firefly — with two hit shows under his belt, he was the writer of several huge movies. And now he was bringing his patented mixture of rollicking adventure and twisted artiness to a space opera. Sure, Firefly's "Cowboys in Space" thing may have confused people at first, but the show really does sell itself, after just a few minutes' viewing, thanks to vivid characters. The failure of the TV show didn't just damage Joss Whedon's career — it damaged media SF as a whole, helping to push us towards canned remakes and reboots. And Firefly's demise was just the first of a trail of broken dreams and disappointments, culminating in the cancellation of Terminator: The Sarah Connor Chronicles and the burial of the promising Virtuality.

NASA and the space program. The decade did hold some great achievements for NASA, including the Mars rovers and some probes traveling outwards into the solar system. But it's hard not to feel a bit crushed by the fact that NASA is retiring its fleet of space shuttles without having a replacement lined up. We're going to have to hitch a ride with the Russians from here on out, and it feels a bit, well, disappointing. Especially with science-fiction promising us that this is our time to explore the solar system and beyond it, the stars themselves.

Ang Lee's Hulk. Before this movie came out, I would have sworn that Ang Lee never made a bad film. His track record included arthouse sensations like The Wedding Banquet, The Ice Storm and Sense And Sensibility, but also the brilliant actioner Crouching Tiger Hidden Dragon. He was also perhaps the most artsy director to take on a superhero icon to date (no offense, Tim Burton). There was every reason to believe Hulk would be both epic and heartfelt — but instead, we got gamma-irradiated poodles, daddy issues and a Hulk who sulked. We probably won't ever get a really great Hulk movie now, after two failures, which sucks. The Hulk deserves a proper outing, in which he fights monsters and marauders and crushes buildings. The Hulk needs to discover that he's not the worst monster in his world, and have larger-than-life adventures. Ang Lee just wasn't capable of giving that to us.

The Matrix sequels. This seems like a no-brainer in retrospect, but maybe you need cyber-Colonel Sanders to take you back and explain to you how much we were all looking forward to The Matrix 2 & 3. Ten years ago, The Matrix was the freshest thing to come out in ages, despite playing on ideas that books had explored for years. Its blend of fetish and noir and cyberpunk and Hong Kong action felt viciously original. And there were just so many ideas for the sequels to explore, so many mysteries about the machine world to uncover. And then... we just sort of descended into muddle. And long rave scenes. And blind Jesus. Walking out of The Matrix Reloaded, I remember someone turning to me and saying, "Well, that wasn't even the best powerpoint presentation I've sat through lately."

Identity Crisis and Infinite Crisis. DC Comics' biggest "event" storylines of the mid-2000s seemed to be groping towards a more adult, more flawed view of their major superheroes, with some of comics' most talent writers on board. But they overshot, landing in angstville and bombarding us with retcons that rewrote the "Satellite era" of the Justice League. As if in an attempt to capture the cachet of Alan Moore's Batman: The Killing Joke two decades earlier, these stories gave us female heroes being raped or abused, and turning into murderers. And Batman saying to Superman, "The last time you inspired anyone was when you died." The melodrama was thicker than the walls of Superman's Fortress of Solitude, and yet when it was all over, it was hard to understand what any of it had been about. The superheroes were closer to a bickering family (calling each other by their first names all the time) and the threats they faced seemed more existential and less external.

Superman Returns. There were a slew of other disappointing superhero movies in the past decade — but mostly you knew going into them that they were going to be ass. Who really thought Brett Ratner would make a good X-Men movie? Even Spider-Man 3 showed every sign of being ass-flavored long before it came out, despite Sam Raimi's involvement. But this film was Bryan Singer coming off two great X-Men films and The Usual Suspects, and he was doing the gutsy move of making it a sequel to the two Donner movies instead of going for the standard-issue reboot. Singer doing Donner — how could it be bad? Uh. Well, there's the part where he changed Clark Kent into Stalkerman. And then there's the Son Of Superman thing. But also, maybe, there's just the fact that the Donner movies were of a different era, and you can't bring that back.

Heroes seasons 2-4. Just imagine, for a moment, if this show had lived up to the promise of its first season. I know it's almost impossible to picture it, but just try. This mutant soap opera thrived on showing us the complications and craziness that come from secret super powers, against the backdrop of a sinister mutant-hunting conspiracy and a super-powered serial killer. But the show wrote checks it couldn't cash, including showing us Claire growing into her heroic destiny and Hiro becoming a future shaved-headed badass. Most of all, the show ducked out on its very title, opting to show us histrionics and family squabbles in place of actual heroism.

Watchmen. It was perhaps the greatest graphic novel of all time — almost certainly the greatest superhero comic of all time — lovingly recreated on screen by the ultimate OCD nerd. Every panel of the comic, recreated as concept art, then as storyboards, then as living, breathing people in costumes, surrounded by CG. Finally, a movie made by us for us. Except. The result, though lovely as anything, looked sort of lifeless once you took it out of the Smashing Pumpkins music-video trailers. The characters didn't quite live and breathe — especially Silk Spectre II, who needed to be the heart of the story. And the ending wasn't just missing a giant squid, or some other huge monstrosity to replace it — it was also lacking a certain coherence and urgency. Once people start talking about power signatures, it suddenly turns into an episode of Star Trek: Voyager. Maybe Watchmen could never have lived up to the book, but it could have been more thrilling than this, with a different Silk Spectre and a more thunderous ending.

Battlestar Galactica's big finale. I know that opinions will differ on this one — but just consider. BSG's finale was one of the most hyped things of recent years. We read endless interviews in which Edward James Olmos, Ron Moore and various others told us that the final episode would shake us to our very cores, and make us weep and smear paint and throw up on ourselves. Meanwhile, Syfy ran promos over and over again that said that "All Will Be Revealed," and I don't remember an asterisk leading to a disclaimer explaining that "All" in this context actually meant a limited number of things, not including how Starbuck came back from the dead or what the hell was up with the Opera House. Even if you think this was the most brilliant conclusion in history, you have to admit BSG promised too much.