Any anime fan can tell you that music is an integral part of anime. Mostly because Japanese music studios use their theme songs to pimp new/hot bands and drive sales, but also partially because this music is often god-awful. While no means a complete list, here are a dozen of the most terrible opening themes anime has to offer.
1) "Tatsumaki Wave," Master of Martial Hearts
While the show is about Japanese school girls who fight primarily by punching each other's clothes off, the problem with this song is that the singer and the band are apparently performing two vastly different songs in two separate locations. I think the singer might have recorded her part in a bathroom somewhere? Sure, they manage to harmonize occasionally, but it's still bad enough someone felt the need to stab the singer at the end.
2) "Shinryaku no Susume," Squid Girl
Honestly, this song is just bouncy J-pop at its high-pitched, overenthusiastic bounciest. It's a little hard on the ears, but it does make sense as a song. But that intro where tortured harpies repeatedly shriek "SHINRYA! SHINRYA! SHINRYA!" is pure torture, plain and simple. It was made out of pain and hate, by people so unrepentantly evil they they wanted others to feel their misery as much as they felt their own. And they just happened to be 20-something Japanese J-pop stars.
"3) Abnormalize." Psycho Pass
Starts out kind of normal, doesn't it? That's how this opening gets you. You listen, and it sounds like a reasonable rock song, and then you wonder: Why isn't the singer singing in a normal voice yet? Why is he still trying to pretend to be a soprano? Is he singing by inhaling? And that's when the other musicians just start playing random notes and the true madness begins.
4) "Utauyo!! Miracle," K-On!
What would happen if you took an already disturbingly perky song and gave it the Alvin & the Chipmunks treatment? I believe the result would be akin to this theme from the popular anime K-On — an incomprehensible mash of high-pitched notes and music played to fast to achieve any sort of melody. On the other hand, I'm pretty sure this song is even more horrible for dogs and other animals whose hearing range exceeds our own.
5) "Go!Go! Maniac!" K-On!
And yet "Utauyo!! Miracle" is a goddamned Beethoven symphony compared to the nightmare than is K-On's second opening theme, "Go!Go! Maniac!" This song isn't music, it's a hate crime. It's some kind of terrifying experiment to see if humanity can make a song that turns us all into violent maniacs. The way I find myself covered in blood and with no recollection of the last few minutes after I hear this disaster is proof that it seems to work.
6) "Take It! Sailor Uniform," Lucky Star
Part cheerleading chant, part rap, part Lovecraftian void of darkness and despair, this "Lucky Star" theme may be the worst Japanese song on this list, and I say that having just called one a hate crime. I refuse to believe that even in Japan, where anime and cuteness drive both their culture and the economy that anyone made this song with the intention that people 1) enjoy it, 2) not hate it, or 3) vow to hunt down and murder those in cold blood responsible for it. This tune is a scathing indictment of an entertainment genre, a cultural paradigm and an entire country, one designed to cause as much physical and emotional pain as possible. Also, it's not very good.
7) German Opening, Naruto
Not all terrible anime opening have to come from Japan, you know. This German opening is proof that any country can fail miserably, especially if they stick a random dude in a recording booth, tell him the show's name and no other information, and then force him to freestyle rap an entire theme song. Why is it in English? I have no idea. But I refuse to believe anybody actually wrote these lyrics down and thought to themselves "Good work."
8) "Neko Mimi Mode," Tsukuyomi Moon Phase
At first, this sounds like a low-key, kind of goofy music reminiscent of the soundtrack to the videogame Katamari Damacy. It's not great, but it's kind of relaxing — and then you start watching the music video and you realize you're currently watching what David Lynch sees in his nightmares, and you try to tear your eyes out of your head.
9) "Kotodama," Shigofuni
I don't know what J-pop's current fascination is with playing completely random notes on keyboards and then basing entire songs on whatever the hell they crapped out, but this song is clearly a victim of it. There's a fine line between "sounds" and "melody," and "Kotodama here is so far in the "sounds" side "melody" doesn't even show up on its Google maps.
10) "Kyomu Densen," Another
Hey, it's the musical equivalent of Frankenstein's monster! Eighteen different songs, fragments of which are forced together against the laws of nature and God And just like Dr. Frankenstein, the composers of this "song" created one monstrous entity, hideous to perceive, full of hate and despair, and looking to kill for its unnatural, doomed existence. Neat!
11) "Kitei no Tsurugi," Linebarrels of Iron
And now a song that combines most of the worst aspects of all the previous songs together! No melody! Random notes! Trying to force completely random songs together and ending up with a pile of shit! Does… do Japan's anime soundtrack composers get paid by the note?
12) U.S. Opening, One Piece
Talking shit about 4Kids first attempted "cool" theme song for the U.S. release of One Piece, is a bit like talking shit about Hitler — plenty of people have done it before. But much like Hitler, the U.S. One Piece theme song deserves all the scorn it can possibly receive, from now until the end of time. Now, I would like to state unequivocally that Hitler was of course a greater evil than the One Piece theme. However, I would like to say that if Hitler had heard this song, he would have loved it — that's how horrible they both are.