In the first chapter, after getting scolded, Pinkie Pie's daughter Tootsie gives her mom Puppy-Dog Eyes and is somehow able to conjure sad violin music from nowhere.
Sweetie Belle, dangling from a winch as part of her preparations for playing Princess Celestia in an opera, slips into Ye Olde Butcherede Englishe when she wants to be let down for lunch.
"THIS DOTH PLEASETH YOUR PRINCESSETH AS WELL! LOWER ME, BRAVE SIR BOBBIN, SO THAT I MAY PARTAKETHETH OF YONDER FOODETH!"
Twilight's attempts at testing her early models for the wings.
The description of a "both barrels" Fluttershy Stare. It apparently is an actual force of destruction.
The hilarious contrast between the super-uptight Luna first seen in "Luna Eclipsed" and the super-casual one seen in this fanfic.
The reveal that Diamond Tiara has grown up to marry Prince Blueblood.
Luna: Truly it can be said that you two richly deserve one another.
That's nothing. Luna makes a joke to Celestia about a changeling infiltrating their house... and then turning itself in to the guards because it was starving.
Which sums up their relationship pretty well; there is just something quite hilarious about how much they hate each other.
Chrysalis' response when the joke becomes a prophesy. "That's just my luck" indeed.
Luna parodying the usual "swear in Celestia's name" thing when commenting to Celestia about the way the group's dolled up for the opera.
"So help me you, they are all just working it tonight."
Luna runs her evening court like a late night talk show.
Luna in general, really.
After being told by Twilight that Celestia finds the opera written about her to be absolutely hilarious — particularly one beautiful but overwrought aria given to the Princess' fictional equivalent — Sweetie Belle runs with it during her performance, broadly and obviously winking at the real Celestia while singing the aria in question. This results in both of the princesses literally falling out of their chairs laughing. Picture that for a moment.
And now picture the barely-controlled madness that ensues when the other performers in the opera, following Sweetie's lead, spend the rest of the performance hamming it up unmercifully.
Professor Destiny's attempt to sabotage Twilight and Pip's test flight in chapter 15 backfiring. He clearly didn't think through a unicorn standing close to a magic-seeking missile…
Plus his encounter with Pinkie Pie near the end of the chapter. She somehow recognizes him despite the name change, the dye job, and the fact that he's covered in soot at the time.
After Pip and Soarin return with help to put out the fire, Apple Bloom calls Pip "my hero" and gives him a big, wet smooch on the lips. Thanks to the fact that he's still wearing the flight harness, Pip immediately becomes the first earth pony ever to get a wingboner.
Pinkie gets another one in the following chapter when it turns out that AJ and Rarity did tell her about the flight harness, but she deliberately forgot all about it because she figured Twilight would want to be the one to tell her.
Apple Bloom and Pip, thinking they have the house to themselves, decide to go make out in the living room... only to find Big Macintosh standing right behind them. He suggests they play Parcheesi instead.
Destiny's second attempt to sabotage the flight harness doesn't go any better than the first, and ends with a sick bird crapping on him.
Sweetie Belle picking the group up at the train station — by yelling for them so loud she temporarily deafens the entire station.
Then, when she recognizes Pip, she comments that he's gotten "sma-hoking" hot and expresses mild disappointment that he and Apple Bloom are going steady. AB responds by clutching Pip's hoof so hard that she actually hurts him a bit.
Barking Pony's brief cameo.
Celestia, Luna, Cadence and Shining Armor all face-hooving at the same time when Twilight hastily accepts Professor Destiny's challenge.
Otto hitting on Diamond Tiara, and her annoyance with it.
Diamond Tiara getting an ambrosia salad in the face…and Blueblood's suggestion to his butler she get another one for breakfast the following morning, while she's raging in another room.
According to Luna, Manehattan used to be called "Mane Hat". It was one of Chancellor Puddinghead's "outside yon chimney" ideas. The other founders never let her christen a new town again after that.
In Chapter 21, while a distraught Applejack drags Soarin off to talk him out of participating in the Pegathalon, Fluttershy gently tries to calm down an overprotective Big McIntosh. And it works, too:
"No glowering at the table, big bunny. And no crushing your sisters' coltfriends' skulls either. Okay?"
Rainbow Dash's reaction when Twilight tells her that Soarin' and Applejack are dating. And then her embarrassment when she realizes that the entire room is now staring at her.
The existence of Flies Like Thunder, a winged buffalo. You may break out the trombones.
Princess Celestia's finding the Flim-Flam brothers have injured another of her guards, this time causing him to crash through the storage tank of a glue factory and land in a mattress factory. As the hospital staff is plucking the excess feathers off the poor Pegasus guard, she's trying to keep her cool while smoke comes out her ears and the sun briefly glows brighter outdoors.
When Lulong the kirin loses his powers of flight and is forced to drop out of the race, a young Earth pony couple offer to give him a place to stay for the night. As a gesture of thanks, he blesses them thus:
He glanced between the stallion and mare as his antlers scintillated with a glow of white magic. "Your house shall be blessed with many children of strong limb and fair aspect, who shall each in turn have a gift for decoupage, statistics, square-dance calling, geography, and badminton." Plowshare blinked at him. "B-badminton…" Honeysuckle's eyes lit up. "Children!"
What happens to the third Pegasus guard sent after the Flim-Flams and Celestia's reaction to it. While trying to catch up to them in Fillydelphia, he ends up being plowed into the glue cloud trap they left behind for the other racers by Flies Like Thunder, and ends up stuck to him. When he calls Celestia to tell her about it, she shouts a Big "WHAT?!" loud enough to wake up Luna (and momentarily shock her back into Ye Olde Butcherede Englishe), before settling into a Tranquil Fury, with flames starting to lick out of her ears.
Flies Like Thunder: Hey paleface! How did She Who Tells The Sun take the news?
Sir Champion: (noting the reddish color of the early afternoon sun) Not well...
Flies Like Thunder's incredibly relaxed attitude to their predicament just makes it funnier.
When Champion gets out of the hospital, it's revealed that the solvent that removed the glue rendered his mane and coat bright pink. His friend/teammate Sir Charger doesn't let him live it down.
Shut up, Charger!
You know Luna's joke above about the changeling who tried to feed on Diamond Tiara and Blueblood and starved? Well, this comes back in chapter 29, when Chrysalis impersonates Diamond Tiara, and Blueblood can instantly tell by how caring she's acting.
Blueblood offers Chrysalis a drink. Her casual response?
"Alcohol makes me spew caustic foam from my splanch."
In Chapter 30 Braeburn, now the mayor of Appleloosa, runs into all sorts of trouble trying to prepare to greet the entrants in the Grand Pegathalon, which culminates in him desperately trying to find someone to present with the key to the city (the Wonderbolts are trying to track down the Harmony Aeronautics team, and the Negasi from Hollow Shades get escorted off to the tavern after overheating in their sun-proof black jumpsuits). He ends up foisting it on the team from Los Pegasus.
"Welcome t' Appleloosa. Here's th' key to th' city!" Golden Bay cast a nervous look at his life partner Granola then held up a hoof of his own. "Whoa. Bad vibes, dude. Nopony's gonna wanna hang here if you're gonna harsh their mellow as soon as they land." The beleaguered mayor snorted a puff of steam out of his nostrils and shoved the key at them with a growl. "Are you two hippies gonna take this here key off o' me, or are we gonna have t' throw pies at y'all?"
Not to mention how they take the camera bulb's flash, which results in their eyes going wide and both of them going "Whoooooooaaaa…"
In chapter 31, when Destiny and Insanity make the the mistake of walking into the Salt Lick. First the bar-tender offers them some cider, which is apparently still a word they never want to hear again. Then the two weather-factory ponies from Cloudsdale give everyone in the room the idea to play darts with them.
"Celestia herself is our patron. You... you wouldn't dare lay a hoof on us!" Air Hammer shared a glance with his partner, then loomed closer as both Pegasi shrugged indifferently. "We'll make sure t' apologize in person t' her highness once we cross da line in Canterlot." Ice Tongs' expression darkened. "She's got a lotta time t' forgive us. Either way, we'll be outta da hoosegow before youze bums is outta da hospital."
In chapter 34, Rarity haranguing one of the crew of the Ambrosia for accusing her of being a changeling. Especially when Celestia's burst of bad temper is timed just right to add to the intimidation factor.
Chrysalis being outright terrified of the Mane Six. She treats them as if they were the harbingers of the Apocalypse.
In chapter 35, Rainbow Dash suggests to her teammates that they cut through Ghastly Gorge to get around a sand storm. When Spitfire and Shootin' Star have doubts, she says it's no problem and even promises to tell the story of how she got Tank while they're doing it. When we next see them, Shootin' Star and Spitfire are in shock, the latter actually being carried in Rainbow Dash's forelegs, and missing most of her tail…and Rainbow Dash is blissfully finishing up the story as if nothing happened.
Rainbow Dash: Oh suck it up, Cap. It only got a little bit of your tail.
Apparently, the Equestrian equivalent of the NATO alphabet is all based on food.
Celestia has another Freak Out! when she hears about the Flim-Flams escaping Sir Concord's battalion. This time, she blows up a tower. Shining Armor gets a shield up in time to protect himself, but not fast enough to stop his mane and facial hair from being burned off. And he seems a little loopy afterwards.
Luna, by now dreading Celestia's Freak Outs, figuring she should probably get some sunglasses before she tells her about Chrysalis escaping custody.
Redtail freaking out over his feelings for Greta, which are messing with his warrior code of honor.
"My thoughts are disordered. It is as if I am mad, or under a spell. Vhy do I care how soft and sleek my maidservant's pelt is? How graceful the tapering of her primary feathers. The vinsome shyness of her smile. The sveet music of her voice. Vhy do I notice the color of her eyes, or how the sunlight shines in their bottomless depths? Vhy am I talking in bad poetry all of a sudden?"
Right before Soarin's duel with Redtail, Apple Bloom gives him a good luck peck on the cheek on behalf of the absent Applejack. This leads to all the other mares giving him more good luck kisses. When the dumbstruck Soarin' turns to Shootin' Star to see if he's ready for the duel:
"NOW THAT THE TWINS HAVE FLEDGED, YOU HAVE NO EXCUSE TO STAY AWAY!" [Fluttershy] looked away, murmuring softly under her breath. "Except preserving my hearing..." She pawed at the ground with a crease in her brow. "... and my sanity."
Even better, he makes a deeper version of Fluttershy's "sheepish grin" squeak when he smiles.
Best of all, perhaps, the description of him is effectively a pony version of BRIAN BLESSED.
How does Celestia deal with the Flim Flam Brothers once they're finally in custody? With a guilt trip. After seeing Equestria's beloved leader burst into tears, Flim and Flam gladly accept twenty years' hard labor on a rock farm.
Diamond Tiara (sort of) reconciling with Apple Bloom, her hatred of whom was the only thing keeping her going when she was lost in the desert.
Diamond Tiara: I'll never forget what you did for me, Apple Bloom. I hate you with all of my heart forever. Take care! Apple Bloom: Yer... welcome? Y'all... take care... too...
Quillina squeeing over meeting Celestia, and fainting when offered to have tea with her.
Lulong just shows up at Applejack and Soarin's wedding unexpectedly, and explains that he felt drawn there, after "wandering the land meeting its ponies, doing good deeds, and getting in the occasional kung fu battle with bandits."