The manga adaptation of Blood+ is horrible. They got rid of half of the original characters, changed the story and didn't explain anything!

I'm a vampire!

I think Negima was rather disappointing due to its lack of the full story. It would have been nice to see Kotaro and the other members of his group shown as quickly as they were in the manga. Also, Kotaro needs a bigger role than just being in the OVA's.

i think the manga adaption to Princess Tutu was just sad
i didn't even get past the first few pages.

@beloved blood:

Yep, I hope it gets remade and follows it better. It is a WONDERFUL manga and I would love to see the other Zodiac members, especially the relationships between them, and see the reaction to Akito's true identity and about her mom and relationships with the others in the zodiac

@HametsuKuro:

Wow, I didn't know the studio did all of that to Fruits Basket. I thought they only made Akito a man, wtf., which basically spoiled the whole thing for me. I'm glad I never watched it.

Code Geass's adaptations all derail from the main story and don't make much sense...coming from the original anime, I was very, very disappointed. Seriously, who cares about Knightmare of Nunnally, or Suzaku of the Counterattack? What the heck happened to the original series?!

The one that takes the cake though was the adaptation of Blood+. Everything was changed, there was a new character (I thought his design was cute, but that doesn't excuse him being there!) for no reason, and his existence was not explained in the least. All of the main cast was there, but Diva's character was a little screwed up. One of the most important (and heart-wrenching) scenes was taken out! That particular scene was very significant for the ending of the series and for Diva. I mean, I'm happy that another character was left alive, but... without that scene...the adaptation just sucked in all different kinds of ways. Ugh, just...ugh.

I didn't like Fruits Basket very much....
Also, the Avatar: The Last Airbender was disappointing. :c

Two come to mind mainly because I don't read that much manga, the manga stories continued long after the anime, and I consider both manga to be works of sick, sick art.

First is Soul Eater. Many will disagree and say that the anime is fine in it's own right. They are true to a point because this anime is actually pretty good. Ultimately, there is a single arc, The Battle of the Brew Arc, in which the story shifts tonally, factually, and logically. In the anime, people start acting weird and outside their defined characteristics. In the manga, it's handled quite tactfully, allowing no stretch of the imagination because heaven know you're going to need it. Ultimately, the manga handles the following arc, the Baba Yaga arc, quite nicely. Unfortunately, that's where the anime ends. Which could have been very good, mind you. There was genuinely four different characters that could have died the anime, and it wouldn't have changed the ending. However, it would add to Maka's conviction, allowing the final result to not come from seemingly nowhere. In the manga, it continues to a level of uneasiness and built up fear for characters lives, you can't help but not look away. The death of Medusa exists in both versions and both have advantages and disadvantages. Manga, however, wins because of being of correct time for the character to leave and...well...there really was no other person better to end that life than Crona. Coupled with a mental breakdown that puts A Clockwork Orange to shame and I say the manga comes out on top.

Secondly, and much more controversial, is BECK:Mongolian Chop Squad. Again, I don't hate this anime. I'd say easy top 20 list. However, what could have been is the story again. While the anime ultimately ends soon after the Greatful Soul festival, the manga takes it as far as the bandwagon is going to go. There's a Japanese tour, an American tour, a second album, collaborations, the band breaking up, Eddie getting shot on the side of the highway, the gutwrenching fate of Koyuki and Maho. There is so much potential for second season that never was delivered on. That would have been a audio visual treat, pushing the rank of BECK higher and higher.

Again, I don't hate these anime. What could have been is my ultimate problem. Just goes to show how slow I am with manga.

Most dissapointing mangs--> anime adaptions were:

• Tsubasa Reservoir Chronicles
• Fruits Basket
• Another

they all made me want to hunt down the animators and stab them repeatedly.

To be honest I can't off the top of my head think of one single adaptation of a manga that disappointed me the most. But one thing that does drive me crazy about some anime adaptations is that they'll do a series that's still ongoing and only cover like say the first three or four volumes. Then they'll either just leave the story unfinished or come up with some weird ending. That drives me nuts. One example of this is Rave Master. Sorry is this was a little off topic.

Fruits Basket. The first few episodes followed the manga to every detail, but then they skipped over a lot of stuff, then went backwards, added content that was never in the manga, and finally added its own ending.

@TimeChaser:

I agree. She has so many great series and none of them have ever gotten a proper adaption. It's quite sad, really. ;w;"

Do adaptations of video games count? If so, then the Tales of the Abyss anime, while not absolutely terrible, pales in comparison to the game. I can't really put my finger on why, exactly, because it was a faithful adaptation [save for a few snags], but it just didn't...grip me like the game did. I guess it's because I just love the game too much.

As for actual manga to anime adaptations, the anime adaptation of Chobits is far inferior to the manga. The first half is just a giant block of filler with fanservice and "tee hee look at the silly naive robot girl", and while the manga definitely started off that way, it stopped after about the first or second volume. Not to mention that the series being half filler means that you could literally skip 10+ episodes and not miss anything before they bring up the actual plot, which is kinda dumb. [Though at least it had a catchy OP and EDs.]

@ChibiSasuke:

In a perfect world though, I'd love to see a proper, faithful, glorious adaptation, because I would love to see the series brought to life.

Well, the anime adaption of Togainu no Chi was absolutely horrid. It was originally a visual novel, if that counts? 8|

@TimeChaser:

Thus why Kaori Yuki works should never be adapted.
Ever.
e____e

My most disappointing anime adaptation of a great manga is Angel Sanctuary. The anime was only an OVA covering the first three manga volumes, and even then the story was horribly adapted, with some essential characters and storylines cut out, not to mention a bad dub.

Dishonorable mentions go to:
Berserk - I will never be happy until they do a proper adaptation of this from the beginning.

Hellsing - The first anime just goes off the rails toward the end because it had outpaced where the manga was at at the time. However at least they eventually fixed this by making Hellsing Ultimate.

The Tsubasa Reservoir Chronicles anime was pretty diappointing; It's not bad the first several episodes, but then all the fillers came and some pretty important parts were left out, if I remember right :/

The manga was a bit confusing near the end, but it's actually pretty good.