- Arc Fatigue: The Mine Arc, where the crew is trying to repair the Gekko, which ranges from roughly Episodes 15-20. Most of the episodes include a lot of Angst on the parts of Renton and Eureka and Holland's abusive behavior towards Renton reaches its upper limits. Fortunately, the Charles and Ray Arc begins almost directly after, which is where the series begins to pick up in steam again, which it manages to maintain for the remainder of the plot.
- Complete Monster: Dewey Novak acts the part of a friendly, charming, noble military officer, but we later discover he put his top fighter Anemone and multiple girls like her through torturous experiments to make them Tyke Bomb soldiers. Anemone was the only survivor and it severely damaged her mind. In order to gain support for his war efforts, Dewey engineers enormous levels of civilian casualties, using the Coralians as a scapegoat to convince humanity they cannot coexist and must wipe out the Coralians. His motivation is that his world domination plans have no place for the Coralians. Most of his motivations boil down to a petty grudge with his younger brother Holland, and he even made preparations to destroy the universe should he fail.
- Ensemble Darkhorse: Charles and Ray for actually treating Renton with respect.
- Everyone Is Jesus in Purgatory: Played with in the soccer episode. Norb says they should play soccer and several people ponder why they're playing soccer. At the end, Norb says something along the lines of "If you had fun, that's good. If you learned something, that's good too."
- Growing the Beard: Starts off inauspicious and mean-spirited, starts picking up once the Beams are introduced, picks up even more after Episode 26, and explodes several episodes later.
- Fanon Discontinuity: Even though (or perhaps because) the movie takes place in an Alternate Universe, many fans refuse to acknowledge the movie's existence. Previously popular characters like Dominique and Anemone getting bridges dropped on them or just plain not showing up, and throwing out some of the themes that defined the original series were also factors that contributed to fans refusing to accept the film.
- They have much the same reaction to Eureka Seven AO for the exact same reason.
- Jerkass Woobie: Anemone.
- Magnificent Bastard: Dewey Novak. Enough said.
- Memetic Mutation: The re-airing of the series on Toonami has created a minor meme in the forums of This Wiki: "Renton Thurston, fourteen years old!" or "It's time for 'Sucky Life Of 14-Year-Old Boy'!"
- Moral Event Horizon:
- Dewey blasts it to bits. Repeatedly.
- Movie!Hap and Movie!Stoner hold down Eureka and rip her top open. What makes this worse is their apparent motivation for doing so—they were concerned about their reenactment of a myth (you know, those typically orally passed down and allegorical stories) not following the story to the letter.
- Episode 6. The kids crying over not wanting to lose their mother may be appropriate for their ages, but it's so overdone especially in comparison to Renton's ordeals that it's hard to take the scene seriously. They apologize to him later, combined with the context and beautiful violins playing in the background does redeem it a bit.
- In "Paradise Lost", Renton struggles with the idea of addressing Ray and Charles as his mother and father. ...anyway...
Charles: (embraces Renton, shoving his face into his own chest) "I worked up a sweat at the gym just now. Do I smell bad?"
(Renton looks up at Charles and shakes his head)
Charles: "This is how your dad smells."
Renton: (tearfully) "It really is a good smell..."
- A few minutes later, Ray makes this face◊ when she finds out who Renton's father is.
- In "Wish Upon a Star", Renton grabs a flower that (presumably symbolically? The ending is a bit strange) appears in Nirvash's cockpit. As he does, there's a "ding!" sound effect like he just picked up a video game powerup.
- Narm Charm: The series practically runs on this. The colors are blindingly bright, the music is sugar-sweet, the idealism is almost offensive, and the way love always conquers all—and then the series finale takes all of these far past Eleven...and by some insane miracle it all works.
- Even the extremely silly and hammy Charles and Ray still work in context given by the time Renton meets them, he's become a fullblown Emo Teen and they're the first people to treat him kindly in years, turning the Narm into a Heartwarmer.
- Never Live It Down: Okay, Holland is a total prick to Renton in the first half of the series. Some people seem to forget that he grows out of it in the latter half and claim he remains an insufferable douchebag throughout. This attitude seemingly stems from the fact quite a people would regard physically assaulting a child just once hard enough to live down. Holland attacks Renton on multiple occasions.
- The Scrappy:
- Those Goddamn kids. Linck in particular. They cry in almost all of their appearances, are completely spoiled, and their continual cries of "Mama!" can become straight up the Most Annoying Sound in the series. Maurice shows his Scrappy colors later on, when they're lost on Earth. "Only love me, mama! No one else!" And then Renton and Eureka just have to go and be so damn understanding about it.
- Holland's general treatment of Renton during the first half of the series is down right brutal at times. The fact he uses Renton as a punching bag on multiple occasions, basically taking out his own inadequacies on a kid, is enough on its own to be loathed by many fans.
- Most of the Gekkostate members get this treatment due to their cruel mistreatment of Renton.
- Take That, Scrappy!: Whenever Talho slaps Holland, you can hear the sound of cheering around the world.
- Tastes Like Diabetes: The ending could cause you to go into insulin shock even if you're not diabetic.
- Wangst: Renton for around half of the first episode. Stays in sight for a while before it evolves into genuine Angst and then disappears.
- What Do You Mean, It's for Kids?: As confirmed by the screenwriter Dai Sato, Eureka Seven aired at 7 AM on Sunday mornings in Japan. The large amount of violence, however, caused the English dub to air at 1:30 am on Adult Swim.
- It is also interesting to note that Studio 23, a channel in the Philippines, aired the Tagalog dub at 10 AM.
- Not to mention that Episode 38 deals with the confusion that Renton was pressuring Eureka into sex (which Renton would NEVER do), and an earlier episode hinted that Holland had sex with Talho.
- In the DVD commentary for episode 20, even the voice actors were astonished by the show's timeslot (especially with regard to the final scenes of that episode).
- What Do You Mean, It's Not Symbolic?: The show has references to Buddhist mythology and The Golden Bough.