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.
Author's Saving Throw: The Blu-ray Selection box of Kira Deco only included 16 select episodes, all of them important to the series' initial plot. However, it causes a lot of Plot Holes as not all the episodes were released due to the series' negative reception.
Awesome Music: All openings and endings are extremely catchy and memorable.
"Strawberry Time", an insert song from the first series used to defeat Dian.
Base Breaker: Jewelina, specifically the Twinkle and Kira Deco versions. Some fans believe she isn't as magnanimous as she appears. In Twinkle, they think she is somehow a bitch for warning Fealina not to go to the human world or that Akari is being forced to clean up her mess. In Kira Deco, they take issue with the fact that she dumped the Dark General and therefore created the main conflict in the show.
When the anime was first announced back in 2009, a lot of Onegai My Melody fans were divided. The hating part think that Onegai My Melody should have a 5th season to compensate for the mistakes of Kirara. The others thought it was great that My Melody was finally put to rest and that it was about time Studio Comet tried something new.
There is a significant divide between fans of the more serious seasons and those of the comedic ones. Expect accusations of not liking Jewelpets if you are on the serious side.
Creator's Pet / Canon Sue: Ruby. She's clumsy and irresponsible, but is also The Chosen One, super-powerful and always knows the right thing to say or do. Also gets very little comeuppance for the crap she pulls. (Remember her abuse of Opal in Sunshine? People chastised her, but she never actually apologized, and later even made a speech to Opal which made her seem like she was in the right.)
Contested Sequel: Kira Deco qualifies as this, largely because most complainers belong to the Periphery Demographic and they are disappointed with how much more childish the fourth season is compared to previous seasons, which often went out of their way to appeal to the otaku crowd. Sweets Dance Princess also had some fans in doubt of whether it's a decent first attempt at a film, or just a big shameless ad for the Sweetspets.
Germans Love David Hasselhoff: Popular in Hong Kong, though less so than in its home country. The USA, for the most part, barely even know this exists.
The franchise was marketed to hell and back when the first series started airing in Europe, but enthusiasm for it died down a year or so later, with a lot of countries only airing the first two seasons (sometimes, not even the second one). Only Spain and Portugal air seasons after Twinkle now, thanks to the efforts of Luk Internacional (to give you an idea, they also brought the entirety of Onegai My Melody), likely because they have some kind of deal with TV Tokyo or Sanrio.
Onegai My Jewelpet Kirara Deco for Kira Deco due to its plot being highly similar to Onegai My Melody Kirara. And note that both of these series are considered the worst incarnations, except that Onegai My Melody Kirara turned out to be a Franchise Killer for the My Melody anime.
Code Dian: Andy of the Rebellion.* In episode 36 of the first series, Dian transformed into a human guy named Andy Samael, who actually looked like Lelouch. Fittingly, he is voiced by Jun Fukuyama which fits his role as a Magnificent Bastard.
Keigo Tatewaki, the lost member of Celestial Being.* Fans had no idea who Tatewaki's voice actor was when the series first aired. Then the ending credits revealed that Mamoru Miyano was doing his voice, which is hilarious considering he voiced Setsuna. Miyano doesn't usually voice Butt Monkeys. Until the gag OVA of the series and some CD Dramas showing Setsuna's humorous side were released, fans were rather shocked with Miyano's role.
Pretending to be Kira Deco-era Angela and Labra and arresting people for saying something which ticks them off (like Fandom Heresy).
"Everything is Ruby's fault."* Because of the reveal at the end of Happiness and Ruby's reputation to cause disaster wherever she goes, fans have taken to joking that the major crisis driving an anime's plot is Ruby's fault somehow. The funny thing is that this is only true of Happiness so far.
Memetic Sex God: Judging by the fanart, Garnet and Macaronia for the pets, and Akari and Kanon for the humans.
Moe: Yamirin from Kira Deco. It helps that she was designed by an in-universe otaku.
Most Annoying Sound: "SAWA! YAKA! SAWA! YAKA! SAWA! YAKA!" would be more tolerable if it weren't repeated loudly and ad nauseam by Hisashi.
Labra's crying can definitely make your ear drums bleed.
Narm: Labra's death in episode 51 of Kira Deco loses all its impact when they show Angela's shocked reaction, which is super-deformed.
Nightmare Fuel: Episode 25 of Kira Deco, featuring a village of saury. Coal casts a spell to rot its inhabitants, and we get to see decaying zombie saury as a result. Then the unaffected saury decide to commit suicide by throwing themselves in a fire, to avoid becoming spoiled food. Yes, they do see themselves as food, and think it's a great honor to be killed and eaten by other beings. Even if the show treats the whole situation as absurd, it's pretty freaking horrible when you think about it.
The scene in the movie where Park morphs into his monstrous form will most likely startle first-time viewers.
No Yay: Reaction of the fans who aren't okay with human-Jewelpet romance.
Pandering to the Base: Kira Deco is the end result of what happens when something aimed at little girls excessively panders to the periphery demographic. The anime has done this since the beginning, but the first series had small doses of it and Twinkle had a reasonable balance. However, Sunshine truly spoilt the secondary audiences too much (18-year old characters worried about their future, taboo love and a myriad of obscure pop-culture references are a winning combination for otakus, but not for little kids) and shot their expectations for Kira Deco far too high. Hence, the outrage of the secondary audience when Kira Deco turned out to be Lighter and Softer so it'd be more appealing to kids (its main demographic) again. The Blu-Ray Selection box is just another example of surrendering to the periphery demographic.
Pink gets a lot of Costume Porn thrown on her to appease the older (male otaku) audiences.
Periphery Demographic: At first, the entire franchise appealed to girls only. It was with the release of Twinkle that the series started pandering to the older demographic, including otakus. That is because Twinkle has the producer of Tokyo Mew Mew and Nanatsuiro Drops in charge.
The Scrappy: Ruby gets this to a lesser extent. Being the mascot and the protagonist does give her her share of haters, due to overexposure. Of course, some do find her genuinely annoying as a character.
Uncanny Valley: The Jewelpets in the first series have eyes with a weaker shine than in following seasons. This might make them look more like puppets than living beings.
The first series' non-Jewelpet character designs can also come across as this to some, due to how gaudy and just plain weird a lot of them are.
Viewer Species Confusion: Io and King. The first one is a particular species of rabbit characterized by having droopy ears; it's easy to think that he's a dog, especially in Twinkle, where he forms a trio with two dog Jewelpets; it ended up being lampshaded in Happiness. As for King, he is supposed to be a French bulldog, but his color scheme makes him look like some sort of creature who decided to wear a pink rabbit outfit... with a pig-like tail. Truly the stuff that Mind Screw is made of.
Woolseyism: In episode 1 of Kira Deco, Opal calls Ruby 'Baka' and a discussion ensues about how Opal is more 'baka' because the word needs the characters of 'horse' (which Opal is) and 'deer' to be formed. In the Portuguese dub, Opal calls Ruby 'burra', which means both 'stupid' and 'donkey', and Garnet remarks that she is more 'burra' because of the closeness in species between horses and donkeys.