In Alicorn's Shadow, while trying to solve a riddle about the stars, Daring lists all of the possible constellations visible during the spring equinox but she apparently leaves out one - the dragon. At first, fans thought it was just a mistake. However, after the release of Legacy of Nightmare Moon, it takes on a whole new meaning. The Dragon constellation didn't exist yet in the Daring Do universe because Inti becomes it at the end of Legacy of Nightmare Moon
In Cove of Candles Daring theorizes that Miss Starlight's whining could be weaponized. Well, this tropony has a cousin way out east in Ponyville who successfully employed whining against some (admittedly wimpier than normal) Diamond Dog captors, keeping them off-balance until her friends arrived to subdue the Dogs.
Sweeney's attitude toward griffons hints that his wife was killed by a griffon, but then you wonder why he'd take it out on ponies. Then it hits you: griffons probably didn't kill his wife, but they would be incredibly apt at discovering horse meat.
Mrs. Hoovett seems a little too eager to get Linnet out of the bakery. She doesn't want Linnet to be around Sweeney long enough for him to learn her name or notice that she has his eyes.
Why does the Assembler hate Omnicidal Maniacs so much? Simple. It was created to combat one.
In Mirror Pond, Greyhoof describes some inventions his village refuses to use (like the bow and arrow) because they were invented under the influence of cutie pox. Well, ingenuity can sometimes be a side effect—chess grandmaster Geri Haltarov recently admitted that a gambit he defeated several opponents with in recent games was actually first used to defeat him by a filly whose cutie pox made her the greatest chess player ever. Look up "Ailing Apple trap" on Whinnypedia for more information.
Which is strange because the bow and arrow were developed independently by both griffons and minotaurs. Also, how would they be able to use them? They're Earth Ponies.
With the Colt of Smooze, the abuse directed toward dragons makes a lot of sense when you remember that the Colt Leader was abused by a dragon herself. She'd probably instill in her followers a sense of hatred toward them.
Why is Applesack more bigoted than the other members of the Colt? Well, the Apple Clan has always been rather conservative, and she just takes it to its logical extreme.
Why does Count Vryko get physically ill around Bravado? Bravado loves spicy foods, including garlic. Presumably, there are subtle traces of it on him, enough for Vryko's enhanced senses to detect.
Rayback's ability to appraise the worth of gems seems odd... until you realize he's a dragon, meaning that he can judge quality with the skill of the best jeweler.
Why does King Metamorphosis think his Queen is so beautiful? Well, she may be ugly by pony standards, but to the changelings, she's a paragon of beauty. The reason? Her physical traits are signs of fertility, which every species is programmed to find desirable.
Here's one from The Ring Of Destiny: At first Ahuizotl's plan seems to make no sense. But then I remembered that it's not just his name but his species too. An Ahuizotl is a water-dwelling ambush predator from ancient Amareazon legend that eats specifically eyes, teeth and hard keratin such as claws or hooves. To eat he has to take ponies by surprise as they enter the water. By increasing the world's temperature, he'd be making taking a short dip in this refreshing looking lake on a hot day even more irrisistable than it usually is, ensuring he gets a steady stream of food. Basically, he's ordering free takeout for the next eight hundred years.
The final chapters of Cove of Candles and the truth behind Blackmanes curse imply that the entire middle third of the book(from Daring's arrival at the Secret Shipyard to Ahuizotl's appearance) took place wholly in Daring's mind. Furthermore, the implications that Blackmanes crew is composed almost ENTIRELY of ponies that had come in search of the treasure previously, and that Daring was VERY close to taking Blackmane up on his offer to 'join the crew'.
Precisely how long has The Wooden Mask been around?
How many ponies had Sweeney Trot gotten to before Storm Talon found him out?
In the aftermath of the fight with Sweeney, Storm is secretly drinking hard cider. No big deal, right? Until you realize he's not an equine. Alcohol has much more pronounced depressive effects on the biology of primarily carnivorous species. Considering he was on painkillers at the time, and his line about drinking himself to death as opposed to lashing out like Sweeney earlier, between Lightning Kicker's death and seeing so much of Sweeney in himself must have put his mindset in a very dark place.
What kind of threat would warrant the Assembler's creation? Is it still around today?
It's implied to be Krastos.
The Colt of Smooze consisted of ponies who have horribly suffered and its members were in close proximity to the Smooze. The Assembler mercilessly tore apart ponies who were depressed and corrupted.
Not to mention the entire point of the Assembler: Creating and ordering soulless creatures. This thing has an army under its command. Luckily, it doesn't seem to be interested in actually ruling anything. For now.
This tropony has a cousin on a farm near Ponyville who swears up and down that the village from RotBV is real and that the Nightmares nearly made her one of them when she got separated from her sister's best friend after visiting a hermit in the Everfree Forest. And that branch of the family has a reputation for honesty.
Wait, wasn't that same filly involved in the Gabby Gums scandal?
Plus, she once tried to make me buy a huge sack of apples she put in my bags and claimed I took. Not to mention I heard from the other mares in my voice-acting class that she caught Cutie Pox after she stole from that same hermit.
Add to that trying to trick her Manehatten cousin into driving off a cliff over some personal dispute! We're not exactly dealing with a paragon of honesty here!
From what I've heard from a certain unicorn at the library, the filly has an older sister who's honest. The other parts of the family, maybe not.
Applesack mentions she once drowned a sack full of puppies. That's morbid enough as it is, but considering that Applesack is heavily implied to have been a war criminal and the war was against the Diamond Dogs, that has some very disturbing implications.
Ahuizotl has to constantly replace Mr. Tibbles to have a cute kitten in his entourage. Considering what a psychopath he is, what happens to the other Mr. Tibbles'?
One of the universes has Ahuizotl and Daring as Sickeningly Sweethearts—and some of the endearment terms this tropony had once heard a couple under the Hearts and Hooves love poison utter. "Kissy-wissy snuggy-wuggy sugar bear?" I'm all for romance, but...
Why would the deathtrap room in the first volume have the activation lever on the inside of the trap, other than to provide Daring with an opportunity to escape? It's pretty obvious that placing it outside the door would have been fatal to the hero.
Maybe so whoever uses it can make sure it works.
So the victim would struggle, making their demise all the more horrifying.
Perhaps it was a test, of the nature that if somepony escaped the trap, they were innocent
Why does Count Vryko Lakas appear in Trial if Daring Do didn't do anything to upset him?
Probably the same reason Rex and Inferno are there, even though their primary beef is with Ahuizotl.