Note: references that appear in both the anime and the manga are only listed in the anime section.
Anime
Season 1
Episode 1
- The first scene ends with a reference to the Japanese Twitter meme "They had lots of sex afterwards".
- Hajime is watching Engaged to the Unidentified.
- When Hajime declares he has no desire to work, he gains a scar similar to Kenshin from Rurouni Kenshin.
- Hajime quotes Setsuna from Mobile Suit Gundam 00 when Kaoru is looking at his porn magazines.
- At one point, Hajime is looking at a screenshot of Nanoha from Magical Girl Lyrical Nanoha StrikerS. When he turns around to face Kaoru, the "Newtype Spark" effect from Mobile Suit Gundam plays.
- Two of the movie posters are from Mobile Suit Gundam Unicorn and Puella Magi Madoka Magica the Movie: Rebellion.
- Hajime's critique of the movie is done in the style of the second Patlabor movie.
Episode 2
- During the eyecatch, Youta mimics the cover of Oreimo.
Episode 3
- The title of the episode is a parody of Oreimo's full title.
- Youta mentions wanting to do some "Yosuga-ing" with Hajime. This is a reference to Yosuga no Sora.
- Hajime mentions that his plan to get Youta friends should work "thinking in Oreimo terms."
Episode 4
- Hajime quotes El Shaddai: Ascension of the Metatron at the beginning of the episode.
Episode 5
- Krauser II of Detroit Metal City appears behind Kaoru when Hajime mentions how she acted while drunk. She also apparently said that she would "rape him ten times in one second", which is another reference to Krauser.
- At the end of the episode, Hajime compares the things that Kaoru said to sounding like something out of the monthly hentai manga magazine Comic Kairakuten.
Episode 8
- The title of the episode is a reference to the sports manga Pro Golfer Saru.
- During the eyecatch, Kaoru appears as Backbeard from GeGeGe no Kitarō and says "you damn lolicon", an internet meme associated with the character.
Episode 9
- Hajime's room has various figurines, including Cattleya from Queen's Blade and Mikuru from The Meloncholy of Haruhi Suzumiya. There is also a picture of Madoka from Puella Magi Madoka Magica.
- When Hajime leaves for his date, Youta mentions he forgot to bring "Ai Plus" (a parody of Love Plus for the 3DS).
- The character shown on the 3DS is Ranpha from Galaxy Angel.
Episode 10
- Hajime and Kyouko reenact part of the door scene from the first arc of When They Cry: Higurashi.
- During Hajime and Kaoru's discussion over a name for their child Hajime references Neon Genesis Evangelion twice; he dresses up like Gendo and suggests Shinji or Rei for a name, and he cites Kaworu Nagisa as an example of Kaoru's name being used in anime. The eyecatch that follows is Kaoru dressed up like Kaworu and in his famous sitting pose.
Episode 12
- Hajime is on the Google homepage at the beginning of the episode.
- Next to his computer are two volumes of Grisaia no Rakuen.
- The first three shots of the episode are a parody of the opening for Mobile Suit Zeta Gundam.
Episode 13
- The official Crunchyroll release of the episode was accompanied by the caption "Congratulations to all the children. This and the congratulations scene later in the episode are both references to Neon Genesis Evangelion.
- The shot of Kaoru's pregnancy test turning positive is a reference to the Pregnancy Announcement Meme.
Season 2
General
- Luffy's straw hat from One Piece can be seen hung up in Hajime and Kaoru's dining room at multiple points throughout the season.
Episode 1
- The Chinese master chef that Hajime mentions is Mao from Chūka Ichiban!
- In the first eyecatch, Kaoru is dressed as Pino from Valvrave the Liberator.
- The voice search on Hajime's phone sounds like a Dominator from Psycho-Pass.
- When Kaoru punches Hajime the second time, he ends up in the same pose as Yamcha's death scene in Dragon Ball Z.
- The second eyecatch is Nozomu as Ippo from Hajime no Ippo.
- Hajime briefly wonders if Akiko was a Terminator, complete with the baseline from the series theme and her saying "I'll Be Back" in English.
- The episode ends with the same "They had lots of sex afterwards" meme as the first season.
Episode 2
- When worrying about their compatibility, Kaoru imagines herself and Hajime as Sailor Moon and Tuxedo mask from Sailor Moon when looking up information on compatibility. When she looks up astrology she imagines them as Gold Saint Sagittarius and Cancer from Saint Seiya.
- At one point, Hajime is wearing the Cardboard Gundam suit and quotes the beginning of the Mobile Suit Gundam opening theme.
- The "To Be Continued" arrow at the end of the episode is taken from JoJo's Bizarre Adventure.
Episode 3
- Hajime is shown to own all three of the 8th generation consoles.
- Hajime has figures of Rika and Mika from The iDOLM@STER: Cinderella Girls (with the hair colors swapped).
- Five plastic Gundam models are shown next to the fax machine.
- Hajime's room resembles the Sea of Corruption from Nausicaä of the Valley of the Wind. Kaoru is also wearing the same face masks as in the movie.
- Hajime and Kaoru's bowling team name is TYPE-BOON, a reference to the developer TYPE-MOON. Hajime also shouts out "Excalibur", a reference to the character Saber from Fate/Stay Night. The official Crunchyroll release continues the references with the episode description being a reference to the character Archer.
Episode 4
- The title of the episode is a reference to the anime Free.
- Hajime owns a black XBox 360.
- Youta's favorite manga is Tokyo Ghoul.
Episode 5
- Hajime's suggested bowling team name was Little Busters. Miki's response was that "he has no interest in finding out the secret to the world" a plot point from the same visual novel.
Episode 6
- The Episode number (-108) could be a reference to the Bleach arc "Turn Back the Pendulum" which started on chapter -108.
Episode 8
- When protecting Youta, Hajime mentions "The Organization" a group from Steins;Gate.
Episode 9
- Hajime mentions that he's "with the Witches" while wearing cat ears and jet sounds playing in the background. This is a reference to Strike Witches.
- Hajime's New Year's gift to Youta has a green Doraemon on the envelope.
Episode 10
- Hajime is watching Himegoto when Kaoru is wondering about the possibility of him cheating on her.
Manga
Chapter 3
- The cover image is Kaoru and Hajime dressed up as Jam Kuradoberi and That Man from Guilty Gear. The two of them later play the game together.
Chapter 5
- When talking about meeting Rino and Tanaka, Hajime says "I'll destroy that illusion of their's", the catchphrase of Touma from A Certain Magical Index.
Chapter 6
- Hajime and Kaoru play Yu-Gi-Oh together. Kaoru has also read Yu-Gi-Oh R.
Chapter 7
- Hajime and Youta have a Gundam quiz.
- Hajime was playing Monster Hunter 3 while he was at the beach.
Chapter 51
- Kaoru is wielding Raising Heart from Magical Girl Lyrical Nanoha on the cover.