These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Daily Life with Monster Girl
Arc Fatigue: The mystery about who "D" is. So far "D" has been hinted at, only to not be the case, repeatedly. Draco, Kii, Lilith, and the Dullahan are all not it. The Dullahan at least arrived as a warning, hopefully indicating closure to the mystery soon. Doppel also provided the initial note, but was unaware of the second,.
Broken Base: Fans have been split on the official spelling of the characters' names revealed in chapter 10, especially Meer (German for something between "ocean" an "sea")/Miia.
The dislike of the translation choices in the official english manga has caused not so much a split, but a near-unanimous decrying of it. The translation in itself isn't bad or incorrect, it's just filled with a Hurricane of Puns. Which to some people is a lot worse.
Les Yay: Papi and Suu. Suu notably kisses her outright during her water-absorbing spree in Chapter 10, when she settles for lapping up the water from Miia and Centorea.
Rewatch Bonus: Chapter 22. Toward the end Manako points out that she had seen "D" during the date with Tio. "D" actually was present in the background for all three dates.
Squick: Chapter 20. Very reminiscent of Seikon No Qwaser...
Chapter 14 sets Rachnera up as the manga's first possible villain, yet she was disappointingly added to the harem near-instantly. It would've been more climatic had she been a slightly longer-term antagonist with a sympathetic backstory that became a love interest.
And then there's Draco from chapter 19. Possible rival and villain...and he turns out to not even be an actual dude.
What an Idiot: A funny example. Since Kimihito's death threat, Ms. Smith assigns a member of MON for protective detail during his dates. You'd think Doppel, the shape-shifting infiltrator, would be the perfect candidate for keeping an eye on him incognito; instead, Smith assigns Tio, the dark-skinned, horned giant. There's even a panel where pedestrians look at her in shock while she (futilely) tries to be discreet. Considering Doppel instigated the whole plot, it makes sense she's not available.
In doing this Doppel herself qualifies, as she accomplished the exact opposite of her job. Her prank ended up allowing someone else to send an actual death threat, and judging by the Dullahan's arrival and warning they intend to act on it.
Wheelchair Woobie: Averted with Meron. She is chipper, polite, and only needs the wheelchair when she's not in her room, which has a pool of water to accommodate her.