Americans Hate Tingle: Despite the show being both a massive mainstream and cult success in America, the show has failed to obtain any level of mainstream success in Britain. British TV only aired the first season (on Boomerang, since there's no UK version of The Hub. Although it could happen). Compare this to the rest of Europe, where most countries have aired all currently-made episodes (My Little Pony has always been more popular in Europe than America, and – as happened in The '80s – Hasbro released most of this generation's early merch in Europe first). The series finally returned to British TV in 2013 via Tiny Pop, a channel targeted at preschoolers. It was later moved to the Tiny Pop's freeview sister channel Pop which is aimed at the same audience demographic as Nicktoons. Despite this, Britain has a small yet highly dedicated fandom towards the show, with many fan artists being based there.
Archive Panic: Guaranteed 143 episodes and five movies. That's 80 hours to watch everything uninterrupted.
Awesome Art: Not only are the show's aesthetics and character designs incredibly popular and spawned millions of fan artists and followings, but it is considered one of the quintessential examples of good Flash animation, due to a much larger amount of specific, varied expressions and a generally higher quality in character-acting than most previous users of the method that make it more appealing to watch than even some hand-drawn or CGI cartoons.
Ear Worm: So far, pretty much every song has been declared an ear worm. Naturally overlaps with Awesome Music.
Good Bad Translation: One line in the Japanese version mistranslates Applejack's "Widdle Rarity" as "Peeing Rarity". Most Japanese audiences found this line to be hilarious.
Growing the Beard: It's hard to pinpoint the exact moment the show grew the beard, but generally it is believed to be sometime near the middle of season 1, though some believe that it didn't fully grow the beard until season 2. (Coincidentally, the E/I rating was dropped around this time as well.)
Pinkie Pie's laugh. Since she's the Element of Laughter, it really isn't surprising that her happy little giggle is nice to hear.
Princess Cadance's singing voice.
For that matter, the sound of Princesses Cadance, Luna and Celestia singing in choir.
Narm: Hasbro has taken to using Wilhelm Screams in pretty much every single episode of Season 4.
However, there are a few occasions wherein it reaches Narm Charm levels. Most notably in Season 4, episode 6, wherein the characters are inside an homage to Superhero comics. As well as Season 4, episode 4, which was a homage to Indiana Jones.
Narm Charm: While the show runners are absolutely aware of the older fans and pander to them frequently, at its core, this is still a show for young children. As a result, a lot of time it can be very corny, cheesy, sappy, Anvilicious, etc. But that's part of why the Periphery Demographic loves it, and it's usually done well enough to result in this trope instead of straight Narm.
The bronyfandom is this. Believe it or not, back in the 80s, there were a lot of boys watching G1 due to the adventure-filled plots that were highly unusual in girl's shows at the time. (Obviously, they didn't call themselves "bronies", though.) But since 4chan didn't exist back then, the franchise never caught on as boy-friendly at the time.
Another good example, that's slightly less old, would-be Sailor Moon fans from the nighties gave way to pretty much the same reaction as we're getting now the whole "these guys are a pile of happy cigarettes" from the haters and a "it's the turning point of masculinity" from the fans side.
Painful Rhyme: Crops up occasionally; the show's "songwriter" just composes the music and relies on the episodes' regular writers for lyrics. Pinkie's song in "Over a Barrel" invokes this intentionally.
Similar with Rarity, they also provided a sound effect for Pinkie's uvula wiggling around during her "I'm at the Grand Galloping Gala" song.
Overlapping with Shown Their Work, "The Return of Harmony Part 2" has the ponies' pupil sizes increase and decrease accordingly as Discord screws with the sun and moon.
Seinfeld Is Unfunny: The quality of the writing in the early Season 1 episodes (especially the two-part pilot) may seem quite low to people who are used to watching the later episodes, which have a lot more Parental Bonus and Fandom Nods. This was before Hasbro knew about the show's Periphery Demographic, so it's justified.
Her helmet seemed to be re-used for her Commander Hurricane role in "Hearth's Warming Eve", however.
That is to say, cool for a superhero. For a formal dance... perhaps not so much. Then again, her reason for attending was to crash the Wonderbolts' performance with her flying moves, so it makes sense she initially thought the dress would work.
"Magical Mystery Cure". You know that there's going to be more coming when it looks like the problem's solved and everything's going to be all fine and dandy...with a third of the episode left.
In Inspiration Manifestation, Rarity has made her creative contribution to the Foal and Filly Fair, nothing bad has happened, and she's about to return the book to Spike...and at this point, we're only eight minutes into the episode. She decides to hold onto the book for just a little while longer...
"Crusaders of the Lost Mark": The episode's selling conflict, a class president election between Diamond Tiara and Pipsqueak, only takes up the first half of the episode, with Diamond Tiara cementing her Heel–Face Turn a few minutes afterward.
The scene where the sun is setting in "Lesson Zero" has a suspiciously similar Version of the "Dream is Collapsing" theme from Inception. And in the scene immediately following, The Princess' Speech is emphasized by music from... The King's Speech.
The music playing at Iron Will's seminar in "Putting Your Hoof Down" is actually "Eye of the Tiger" with one note changed. In the same episode, when Fluttershy realizes she's become a monster, the Lonely Man theme from The Incredible Hulk starts playing.
During the scene in the episode "It's About Time" where Twilight Sparkle meets a future version of herself, the background music is suspiciously similar to "I am the Doctor" from Series 5 and 6 of Doctor Who.
"One Bad Apple" features an A-Team Montage while the CMC are building the second float, down to the music.
A parody of the Bonanza theme is often used in scenes relating to the Apple family.
Vindicated by History: Some early episodes concerning continuity changes were criticised for being too quick and lacking proper focus, especially in Season Three. Seasons Four and Five seem to be devoted to furthering the development of these arcs, making said episodes more enjoyable taken as mere pivots than the entire story. "Keep Calm and Flutter On" (concerning the start of Discord's Heel–Face Turn) is a key example.
Watch It for the Meme: This is generally how many fans started watching the show, but quite a few of them actually care more about the show than seeing Lyra/Bon Bon in the background.
This is debatable, as any episode involving an appearance by Derpy can fill comment pages simply pleased with her appearance and nothing else in the episode. The most egregious example was The Last Roundup, which may as well only have been the opening five minutes of the episode.