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.
Award Snub: Heartcatch Precure! The Movie: Fashion Show in the City of Flowers?! was nominated for the Kidscreen Award along side Zhu Zhu Pets: Quest For Zhu and Wapos Bay: Long Goodbyes, the latter of which won. (Want to watch the winning movie? Well, good luck with that!) No word, though, if it did better against Zhu Zhu Pets.
Ensemble Darkhorse: The fandom seems to have quite a fixation on certain supporting characters, particularly Sayaka and Kenji. The latter gets quite a bit of fanart of his imagined alter-ego from episode 21, Cure Fire. There's also a lot of fanart of his mom.
French Love Heartcatch Precure: "Heartcatch Precure!: The Movie" was apparently popular enough in France that it was simple dubbed into French, and has a surprising number of Fans in the West, which begs the question why no Movie Theater/TV Station wants to air that anime film.
The show in general has quite a few Western fans for just being a great show.
Growing the Beard: The series really began to take off after episode 8, which provided great character development.
Hilarious in Hindsight: With his fluffy hair, Kenji Ban could be easily mistaken for a shounen anime character. Two years later, Yoshihiko Umakoshi, character designer for Heartcatch, went on to work on an actual shonen anime.
Unintentionally speaking, Cure Blossom and Cure Marine, inclusing Coffret and Chypre respectively reminds some fans of Robotboy and Robotgirl from Robotboy.
Launcher of a Thousand Ships: There is fanwork pairing up Tsubomi with every other Cure in the series, a number of supporting characters and a couple of villains. A few fans even joked that the series was actually all about her building a harem.
Itsuki, arguably, given how popular she is with the ladies.
Les Yay: Tsubomi gets some in with Erika sometimes, and she still seems to have a crush on Itsuki. To say nothing of Yuri and Momoka...
Yuri's meeting up with Cologne, her deceased fairy partner. Made sadder by the episode making it seem like he would be revived. Instead only his spirit appears before her.
As noted elsewhere, Dark Precure's death is also quite saddening. Many viewers are reported to have broke down in tears during this scene.
Tough Act to Follow: As stated above, this series in particular is considered to be so popular that the few series that come after to be not as good. Considering that until DokiDoki! Precure came along, the ratings for the series in the previous twoseasons after Heartcatch had a rather signifcant drop by comparison. It doesn't help that this series has some of the highest ratings in the franchises history, right after (If not up there) with the original series.
Throw the Dog a Bone: Infuriatingly denied. Even though Yuri has to cope with a machine-gun volley of traumatic revelations and events (her fairy partner dies forever; Saabaku is her father; Dark Precure is her genetic little sister and was created by her Brainwashed father specifically to kill her, only to die at Yuri's hands; her father leaves Yuri to comfort Dark Precure in her dying moments, her father is killed in front of her by the Big Bad) and still manages to save the world, she gets no reward or compensation for the losses she's suffered. It's an incredibly Bittersweet Ending for her character, extremely so by the standards of kids' anime.
Trailer Awesome Decay: Yuri's transformation sequence would have been much more badass and surprising if it wasn't the only damn thing shown in the next episode preview.