Pinkie Pie wanders the streets of Ponyville, and it occurs to her that she doesn't remember how to get home. She lives on Sugarcube Corner – one of the other Pinkies had mentioned that – and she knows, instinctively, that Sugarcube Corner has the best cakes. It's just that, as hard as she tries, she can't recall how to get there.
So Pinkie walks on, trusting her hooves to take her where she needs to go. Twilight had mentioned something about it before – muscle memory she called it, or maybe muscular mamories? – and Twilight's really smart, so this has to work. Because if Pinkie can't remember the way home, what else has she forgotten?
Pinkie's leg twitches and her tail starts tingling, and before she knows it she's standing in front of a hot pink door. The door is attached to the building, and the building to a sign, so she knows this has to be Sugarcube Corner. Only it doesn't seem familiar at all.
It's not the store itself – the construction is lovely, and Pinkie is certain – beyond certain, even; more like absolutely positutely sure – that if she had to live anywhere she'd want to live here. It's her dream house, a gingerbread creation straight out of her wildest imaginings, and she hazards a guess that it even tastes like cookie dough. But when she steps through the doorway and into the warm lights of the café, the place seems alien to her. Alien in a good way, sure – like those cute green skinned creatures that occasionally bounce around at the edges of her vision – but alien all the same.
The feeling gets worse when she enters her room for the first time. Because, crazy as it sounds, it truly does feel like the first time. The furniture is exactly as she'd like it, and the décor simply marvelous, as Rarity would say, but there's a tiny pinching in her stomach reminding her that she really ought to remember picking out those sheets or painting the walls that adorable teddy bear pattern.
But maybe it's normal for ponies to forget things like that. Rainbow's always going on about the weird stuff she finds in her room, so maybe it's not that odd that Pinkie doesn't know how those balloons got there or who left that phonograph on the desk. Maybe she should just be happy to discover all this cool new stuff she must've left there yesterday – like a treasure hunt, only instead of gold coins she's found a bed!
Except that, to be honest, Pinkie doesn't really know if Rainbow's always telling stories about the strange junk she uncovers in her cloudhouse – Pinkie doesn't really know if Rainbow always talks about anything at all. Pinkie can only theorize based on the things Rainbow told her about today, and suddenly that doesn't seem like very much at all.
But aren't she and Rainbow supposed to be friends? Only, now that she thinks about it, Pinkie doesn't really know much about the five ponies she allegedly spends all her time with. Shouldn't friends know everything about one another? Maybe Pinkie's not such a great friend after all.
Only, Pinkie's pretty sure she is a great friend – a spectacular one, even – because Twilight told her so. But, then again, what does she know about Twilight?
This gives Pinkie pause. What does she know about Twilight?
She knows that Twilight is her friend.
She knows that Twilight really seems to value the magical properties of paint, and, by extension, ponies who appreciate those properties.
She knows that Twilight isn't very fun.
She knows that Twilight was willing to risk destroying one her best friends forever, and didn't appear to be all that worried about getting it wrong.
And suddenly Pinkie isn't all that sure why she's friends with Twilight.
Because she's getting the niggling impression that Twilight might have made a horrible, horrible mistake.
After all, shouldn't the real Pinkie Pie remember the name of the princess she's supposed to be writing a letter to?
Author's Note:
Okay, seriously, did it bother anyone else that Twilight's solution to the problem was to make the Pinkies watch paint dry? Because it seems to me that the real Pinkie Pie would be the first to get bored and abandon the task, not the last. Like, she has the attention span of squirrel on speed. Honestly, this whole thing seemed like a convenient way for Twilight to replace the current, and sometimes irritatingly hyperactive, Pinkie with one who will sit still and do what she's told. The perfect, if incredibly creepy, way to canonically retcon Pinkie's personality. Hasbro, what have you done?