- And You Thought It Would Fail: Many detractors expressed worry about the show, especially considering it was advertised as being from people who worked on Teen Titans Go! (in reality, just the same animation development team, though Aaron Horvath is a staff member), but it has proven to be good to many people and profitable for the network.
- Ensemble Dark Horse:
- The side characters had fanart before their names were even revealed.
- Being the first antagonist faced, the Score Creeper from "Spoooooky Game" is pretty popular with the fans.
- Ever since he first appeared in "No Day Like Snow Day", Master Frown was immediately welcomed by early fans for his Adorkable and charmingly villainous personality. Eric Bauza's performance certainly helps out.
- Along with Master Frown, the other Doom Lords have seen a good share of popularity with the fans, being extra villains that pose a much stronger threat than Frown himself does, with cool designs to boot.
- Fan-Preferred Couple:
- Unikitty/Master Frown has slowly gotten some praise by fans, saying that they're actually cute together. On the flip side Brock/Master Frown is also a popular ship thanks to their Like an Old Married Couple dynamic.
- There's also Hawkodile and Dr. Fox, especially following the episode focusing on the former's crush on the latter.
- Genius Bonus: In "Kaiju Kitty", when the gang call out "Shining Mecha Kitty Turbo V!", Puppycorn instead calls out "Shining Mecha Kitty Turbo Five!". Pooch may be dumb, but he knows his Roman numerals.
- Germans Love David Hasselhoff: Although the series is barely aired at all in the United States, it's absolutely HUGE in the United Kingdom. In fact, its popularity there has reached almost memetic levels:
- Its premiere at the Haymarket Odeon cinema was touted as the UK's very first "cat premiere", featuring actual cats, some of which had fake horns on their heads!
- Its UK TV premiere managed to garner 163,000 viewers, beating even free-to-air channels like CITV.
- The episode "Scary Tales", which was aired in America as the 2018 Halloween special, aired months earlier in the UK.
- Oh yes, and the tie-in LEGO sets that were released in August in the US? They were released a full three months early in Tesco stores across the UK, and would later get into LEGO stores and other toy retailers the next month.
- Heartwarming Moments: Anytime Unikitty shows love for her brother Puppycorn, often calling him the most important person in the world to her, and doing anything to make him happy. She really is a good sister.
- Hilarious in Hindsight:
- We now have an idea what Tara Strong's take on Pinkie Pie would have sounded like.
- People initially thought that Unikitty was voiced by Tara Strong in The LEGO Movie. Now this incarnation really is voiced by her.
- As well, Unikitty's Japanese dubbed voice in The LEGO Movie is Miyuki Sawashiro, who also voices Twilight Sparkle in Friendship is Magic, the same role that Tara Strong originated.
- Ho Yay: Master Frown and Brock have a ton of this. Not only is Brock the one thing Frown actually cares about, but "Top of the Naughty List" implies he kisses Brock goodnight (on the lips, even) every night. In "Batkitty", Frown becomes The Joker to Unikitty's Batman... And Brock becomes his Harley Quinn.
- In "Stuck Together" this episode establishes that one of Master Frown's favorite things are Brock's cookies. Additionally, when Brock gives Frown one to calm him down, Unikitty comments on how cute they are.
- "Dinner Apart-y", especially the ending, is full of Master Frown/Brock moments. While they were fighting during the actual party, Brock revealed to Master Frown that it was their roommate anniversary, and he wanted to invite the whole kingdom, but only Unikitty and Puppycorn came. Master Frown deeply appreciates the party, because of how chaotic it was, and blushes while hugging Brock.
- In "Beach Daze", there's a scene in which Brock 'kisses' Master Frown with lovely music and sparkles in the Background. However, Brock did so because he thought that Master Frown couldn't breathe when he was only being tackled by Hawkodile.
- In "Top of the Naughty List", Master Frown was about to give Brock a goodnight kiss, but they were interrupted by Unikitty and her friends busting open the door.note
- Incest Yay Shipping: Unsurprisingly, there are people who ship Unikitty and Puppycorn together.
- Memetic Mutation:
- Moe: Unikitty, Puppycorn, Dr. Fox... Let's just say everyone, for being adorable LEGO-esque Ridiculously Cute Critter, fitting with the show's nature.
- One-Scene Wonder: Lego Batman (voiced by Will Arnett himself) at the end of BatKitty.
- The Scrappy: Really Old Edith for her behavior in "Cheerleading".
- Tastes Like Diabetes: For some, the show can be a little too sweet.
- Viewer Gender Confusion: Combined with her name, slightly masculine appearance, and androgynous voice, it is very easy to think Craig, the moose farmer, is male. However, supplemental Word of God from director Careen Ingle has confirmed her as female.
- Viewer Species Confusion: Some people have mistaken Dr. Fox as a cat on first glance, thanks to lacking the "tufts" that are often associated with fox designs.
- What an Idiot!: In the episode, "Stuck Together," Master Frown loses his body and is left with only his head. Unikitty finds him, and offers to take him to the Doom Lords meeting....if he helps her with her princess duties.
You'd Expect: Master Frown to explain that as a Doom Lord, he isn't supposed to do nice things. Making people miserable is in his job description.
Instead: Master Frown refuses on the grounds that he doesn't do nice things. Unikitty says she won't take him to the Doom Lords meeting, causing him to relent. He only explains this when they're in Frown Town, after they've done her princess duties.
As a Result: Master Doom gets wind of him being nice and fires him.
Fortunately: Unikitty has a meltdown and destroys the meeting room, causing Master Doom to think this was Master Frown's idea and reinstate him as a Doom Lord.
- The Woobie:
- Richard in end of "Film Fest", he won but nobody understood what his movie was supposed to be, much to his disappointment.
- Unikitty herself also becomes this in "Election Day", where during an argument with Master Frown, she declares an election to see who'll be the better princess. This begins to backfire horribly on her, as all her friends, her own brother, and pretty much everyone else in the kingdom other than Dr. Fox, Hawkodile, and Richard, has a huge out-of-character experience, booing off Unikitty and siding with Frown. Dr. Fox tries to help her by giving her a totally not noticeable camera helmet, in order to record Frown in his bad moments, which results in even more bashing when Frown makes her seem like the villain in the story. At the ending, Unikitty gives a speech which finally gets her some love back, but not even the love of her own brother, who votes for Master Frown. This turns out to be All for Nothing, with the candidates votes tying up, and Ted Butter becoming princess, who begins ruling the kingdom with the iron fist.
YMMV / Unikitty!