YMMV / Grand Blue

• Awesome Music: Opening theme song "Grand Blue" by Shōnan no Kaze; listeners agree it perfectly captures the feeling of summer, as the song's rhythm and vocals are in line with the story's light-hearted tone and comedy.
• Base-Breaking Character: Fans either like Sakurako for her character design and taking her Sadist tendencies out on Iori or hate her because of her actions against Kouhei during the Ouma Women's University festival and general nasty personality, alongside a shallow reason for wanting to date Naomi.
• Broken Base
  • The series is meant to be about scuba diving and college life, yet detractors will cite the story spends more time on using Alcohol-Induced Idiocy and Nudity Tropes as comedic devices, with an egregious Fratbro mentality. While it's certainly part of the earlier narrative, Grand Blue supporters state actual diving segments are taken seriously with Shown Their Work in effect, and characters do engage at working towards their graduate. Furthermore, events that are Played for Laughs like the Beauty Contest and tennis match with a rival club are done to ensure Peek-A-Boo stays afloat in their finances when its members do go diving, especially when equipment and its maintenance costs prove expensive.
  • Who's the "best girl" in the series - Nanaka, Chisa, Azusa or Aina? Not only is it possible to pair each of them with Iori and the story allows for it (thanks to the Not Blood Siblings reveal), but all four had explicit Ship Tease moments with him; later on, Sakurako is also added to this discussion.
• Do Not Do This Cool Thing: The Animated Adaptation includes a warning at the beginning of each episode reminding viewers that underage drinking is illegal; all characters in the show are of legal age^*The Anime bumped the first-years from 18-years old in the Manga to 20. Furthermore, the kind of things the members of Peek-A-Boo do - drunkenness, public indecency, wanton acts of violence - are not encouraged in Real Life; Grand Blue is, after all, meant to be a comedy.
• Ensemble Dark Horse: Azusa, for being the character who's most comfortable with her sexuality and Genki Girl traits that's a stark contrast to the other women in Peek-A-Boo, but also her willingness to be part of the diving club's insanity, including her Trolling antics.
• Hilarious in Hindsight:
  • When the Manga was released, readers joked about the title of the series being a parallel to the similarly-named video game, wondering if a Crossover would eventually happen. The writer decided to "announce" in Chapter 42.5 an upcoming Spin-Off aptly called "Grand Blue Fantasy".
  • In the live-action adaptation, the actors who played Iori (Ryo Ryusei) and Kohei (Atsuhiro Inukai) have a lot in common: they previously portrayed different tokusatsu characters with the same surname, Kiryu.
    • Kohei's case is even more hilarious of the scene where he's bowing to the Ichigo and Zero-Two swimsuits, as they have the same names as Kamen Rider Ichigo and Kamen Rider Zero-One's Final Form; Zero-Two.
• Memetic Mutation
  • Grand Blue is a diving Manga.^ExplanationInspired by the same popular Meme "Food Wars! is a cooking Manga", this is used as a reminder to the audience that despite the outlandishness, the story's premise is still focused on diving.
    • Grand Blue is an isekai fantasy.^ExplanationA Twitter post by series creator Kenji Inoue back in 2017 detailed why he thought Grand Blue belonged to the isekai genre: within context of Grand Blue, "isekai" represents "a world where the legal age to drink is different than Real Life", while "fantasy" refers to "the existence of demi-humans who can chug high-grade alcohol in one go". This post was made to coincide with Inoue's belief back then that Grand Blue wasn't going to receive an Animated Adaptation since some characters weren't of legal age to drink, thus the only way for it to happen were for Grand Blue to be considered part of the isekai genre. Post-Anime release, some fans continue to claim Grand Blue is an isekai out of affection for the series.
  • "Oolong tea"/"water"^ExplanationIf someone is offered a non-alcoholic drink, chances are it's either oolong tea or water; however, both are actually vodka mixed with whiskey and just vodka, respectively, in disguise.
    • *uses a lighter*^ExplanationTo confirm the drink that was offered is actually oolong tea or water, the recipient sets the drink on fire with a lighter, proving it's really alcoholic.
  • "SPREAD THE SALT KOUHEI! SPREAD IT!!"
    "GET THE FUCK OUT OF HERE, NORMIES!!!"^ExplanationCourtesy of Helvetica Scans for the Manga, during the Izu University festival, Iori and Kouhei chase away some of the playboys from the Tinkerbell tennis club trying to flirt with Chisa and Azusa while they man Peek-A-Boo's stand; Iori tells Kouhei to use salt (in Japanese culture, salt is used for purification purposes), as the latter hurls it into the air, screaming the second phrase. Commonly used by fans of the series against detractors and naysayers.
  • Nice Body, Chisa^ExplanationDuring Peek-A-Boo's tennis match with Tinkerbell, a chant made by Iori during Chisa/Aina's game is given an In-Universe Woolseyism from "Nice buddy, Chisa!" to "Nice body, Chisa!" Expect this to be used whenever Chisa is having a Fanservice moment, intentional or not, in the series.
  • Screwdriver^ExplanationIn a similar vein with the oolong tea/water meme, this is an attempt at the actual screwdriver cocktail using a literal screwdriver as garnish.
    • Flatheads^ExplanationAn alternate choice for the above meme by using a flat-head screwdriver instead.
  • Titan Faces^ExplanationA Fan Nickname referring to the grotesque, exaggerated and ridiculous facial expressions that many of the characters show throughout the series in comical moments, due to their similarity with the faces of the titular antagonists from Attack on Titan.
    • "There are more Titans in Grand Blue than in Attack on Titan."^ExplanationThe frequency of the Titan Face has led to comments about its abundancy in Grand Blue compared to Attack on Titan, which already has plenty.
• Signature Scene
  • What appears to be a typical Seinen story about college life is instantly undone with the first two-page spread in the first chapter of the Manga, where Iori sees the male members of Peek-A-Boo half- to completely naked playing drinking games. It's in this spread that Grand Blue establishes the comedic insanity the audience are to expect.
  • The "vodka" moment, one of the prime Trolling scenes in Grand Blue, where Iori is tricked by Kouhei into drinking what he thinks is a glass of water; after a Beat where Iori checks what he drank with a lighter, he throws the glass to the ground in a fit of rage. What really sells this is how the Animated Adaptation does it, with a believable performance by Yūma Uchida as Iori.
• Woolseyism: Aina's Aborted Declaration of Love is changed slightly in English Fan Translations^*Specifically Helvetica Scans in a way that still makes it work. In the original, the character drunkenly confesses in a native dialect (sukii toiu yo) before verbally back-pedaling, claiming it's about a shaker (suito); standard Japanese wordplay. The English release remedies this by having Aina confess in a slurred voice (Ah luv ya) and uses the panel of the character holding a glass tumbler in an open hand as an excuse to make a different Pun ("Olives, yeah"), like on martini cocktails.