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.
Accidental Innuendo: Online product descriptions of the toys put certain items in quotation marks to indicate that they can't actually be used as intended (e.g. plastic cake). (This probably has something to do with avoiding lawsuits.) A description with several words in quotation marks may end up sounding like a Hurricane of Euphemisms.
Not to mention they named one of the G1 ponies Morning Glory...
Though G3 has a niche fandom with those drawn to the series since My Little Pony Tales for it's Slice of Life format, who considers anything prior to Tales unwatchable and are against the direction taken by G4 Season 2.
Even G4 has it's own broken base. Again, it's a battle between those who love the show for being hip and for it's pop-culture references (drew there due to Lauren Faust helming the series) versus existing viewers from G3 who love the franchise for it's Slice of Life format.
It gets worse than that. What about the fans who loathe the toy line and all toy ponies vs the ones who want them to appear in the cartoon?
Dork Age: Arguably G2 for the toys, and either Tales or G3 for the cartoon.
Ear Worm: We apologize for putting the song back in your head after all these years. For those who know not of what we speak, watch this old commercial. A lot of the songs, in fact, though "Shine On" and its reprise from Come Back, Lily Lightly stand out. Also "Wish You Were Here". "La la la lee, la lee loo, every unicorn knows it's true!" Not to mention anything the seaponies sing.
Fan Community Nickname: "Pegasis(ter)" or "Filly" for female fans and "Brony" for... well, that title actually appears to have several different meanings. Most often it means either "male FiM-fan" or just "FiM-fan" (that is, a FiM-fan of either gender), other times "male MLP-fan" (that is, any male MLP-fan, regardless of whether he is mostly into FiM or any other incarnation of the franchise), or, finally, simply "MLP-fan" (which of course means a fan of any MLP incarnation and of either gender).
My Real Daddy: American illustrator and designer Bonnie Zacherle, sculptor Charles Muenchinger and manger Steve D'Aguanno are the creators of My Little Pony. Fans of G4 will tell you the only Pony creator that matters is Lauren Faust.
There have been attempts to avert this though. Fans have even ponified Bonnie as an alicorn, much like Lauren made an alicorn OC of herself which fans embraced.
Older Than They Think: My Pretty Pony was the prototype for the series and was released a full year before the introduction of its more famous version. The original model's design was used for Applejack and it came with a "baby pony" that would become Butterscotch. The second model's design resembled Posey in colors.
Spell My Name with an "S": Is it "Katrina" or "Catrina"? Even sources mix them up. "Firefly's Adventure" or "Rescue from Midnight Castle"? Many, many ponies have different names in different countries, leading to this too. There's also Arabus or Erebus, and there at least four different ways to spell Tirac.
The Big Brother ponies can also be mistaken for girls, as they were very Bishōnen and looked almost exactly like the girls at first.
Ensemble Darkhorse: More like an Ensemble Leaf-green Unicorn, though. Her name is Mimic. There is no evidence to suggest that she is the rarest Pony note the rarest Ponies are probably the Twice-As-Fancy Babies, who didn't sell well because they are completely different Pony "breeds" from their adult counterparts, but she is the most sought-after. Just look her up on eBay.
Fan Myopia: So very very very much. Many people would take one look at the show and go "I don't get it. What's the big whoop?"
They Changed It, Now It Sucks: The much-maligned G2 line. Just see for yourself. (For the record, G1 is all the early ponies up to approximately the 10th anniversary or so. G2 was the revival, and G3 is when people stopped complaining.) The G3 line itself later received a makeover and fans were... not thrilled with it. Even later, this photograph from Toy Fair popped up, and while the Ponies are in yet another redesign, their color schemes were surprisingly similar to those of some G1 characters, and the Fandom was quiet. Then the news of Friendship is Magicnote Itself an example. arrived and the rest is history.
The change to the "Core 7" during G3 is very much dislikednote Hasbro decided to only release seven ponies over and over again, along with changing Rainbow Dash's personality and accent.. So is the lack of male ponies, unlike G1 and G2.
Some season 3 and 4 episodes of FIM is pretty much this to some Slice-of-Life fans.