My vote goes to Total Eclipse. It may not be as readily apparent as the other terrible shows mentioned here, but I think that the way the show so disgustingly ruined the potential it showed in the first two episodes makes it so much worse. Plus the cast is just so hateful you WANT to see the BETA rip them apart to stop their incessant bitching. The icing on this curdled cake is how the show has its priorities out of whack. It focuses too much on insipid juvenile "romance" between its disgusting characters rather than the little issue of HORRIFYING ALIENS DESTROYING THE F^&*ING PLANET.

Uh, I'm finished I guess.

See the spoiler.

I admitted it was bad.

Black Rock Shooter (the anime)
The art was pretty good but the plot sucked.

Sengoku Collection is just ugh, had to stop watching

Natsuyuki Rendezvous (yeah come at me) I'm still watching it, but only to see the ending, no clue how people like any of the main characters

La Storia della Arcana Famigla (i never judge an anime until I watch a few episodes. Still doing that I was really bored with it. I hated the characters)

hiiro no kakera(it started out alittle interesting but it was very slow, the main characters were boring. they were losing alot too.)

Knight in the Area is not specifically bad, but it reminds me of a really dramatic over-the-top telenovela.

Just to clear some things, from my understanding Total Eclipse is based in the VN Muv-Luv's universe (of that it's further based off the Muv-Luv Alternative: Total Eclipse novels which were themselves based off the second plot in the game called Muv-Luv Unlimited and it's sequel Muv-Luv Alternative) which was a adult harem/eroge game. So stuff like the first two episodes won't be a main focus of it probably, considering what it's based on. Then again, I could be partially wrong about that. Blue Gender created by Ryōsuke Takahashi (Armored Trooper VOTOMS, Flag, Gasaraki) is like the first two episodes of Total Eclipse though (and more), you should check that anime out if you already haven't.

After watching Brave 10 my opinion definitely changed, it was by far the worst anime I've seen this year. Main plot was terrible, character development was even worse but expect when trying to squeeze 10 different main characters into a 12 episode series. Also had a pretty ridiculous ending. Only upsides about the anime are the famous voice actors and the fighting scenes.

Unfortunately, 2012 has so many bad anime or disappointing anime (anime that look awesome but ends up wasting its potential).

For me, I'm not too passionate about bad anime because....well....I just think "this is a piece of ()&*^ and it's a waste of time" and I move on. Instead, I sometimes get really pissed on anime that seems so very awesome in the first few episodes and then you slowly watch the series spiral downwards into the pits of anime disgrace.

Each is entitled to their own opinion, but for me there's bad anime and then there's horrible anime. Here's my list of 2012 bad / disappointing anime:

Anime that should've never been created:
Saint Seiya Omega (one of the worst in 2012)
Brave 10 (after finishing the series, I wanted the time I spent watching this anime back. This series was pointless.)

Disappointing anime that will never live up to their predecessors:
Total Eclipse (For a series with such good CG, the characters are simply dull)
Sword Art Online (Liked the first few episodes but then it started to seem like an inferior knock-off of the .hack//sign, 1/2 prince or the other "trapped in an RPG game" anime. I'm still keeping my eye out on this series, but so far none of the current episodes have changed my mind.)
Aquarion Evolution (Aquarion was.....ok, not great or very bad, but ok. I think only very good anime DESERVE sequels, but nowadays it seems as if "we have no new ideas, so let's do a sequel of anything and everything we can". Yes I'm also talking to you, Hollywood.)

I guess I'm at fault then for not doing proper research on the show. It's just too bad though, the mecha design was really cool.

I haven't come across any anime this year that I would consider really terrible, but Sankarea and Black Rock Shooter were somewhat disappointing. I give them 6/10. They both started out pretty good, though.

I agree about Natsuyuki Rendezvous. It started off strong but the last three episodes have been way too slow...hopefully it gets better on the next episode...and from what I hear...there are only two episodes left. :/

whyyyyy...... i like both of those shows lol

Still heading my list of the worst anime series I've ever watched - Cardfight Vanguard (I still can't believe they made another series)

Also I've really grown to dislike Bleach

Hiiro no Kakera - slow paced, all they did in this season is loose and they expect me to wait til October for season 2? why not make it 26 eps all - in - all!?

Shining Hearts: Shiawase no Pan - gave me the "WTF just happened?!" feeling. Rick was hot tho.

La storia della Arcana Famiglia - been boring me soo far. I'd continue watch it and see how I'll regret it afterwards.