"You secretly don't want to join the Wonderbolts."
"Nope." Rainbow Dash idly filed her forehoof while Twilight attempted another guess. Twilight had dragged her here to the library to have an "emergency meeting," whatever that was supposed to be. So far, it'd been pretty un-emergency-ful. ...If that was a real word.
"You secretly look down other ponies because they're not as cool as you."
"No. Well, kinda, but that's not really a secret." Rainbow Dash stuck out her tongue while Twilight sighed.
"You want to be the fastest because someone in your life suffered when you weren't fast enough."
"Uh, no. I want to be the fastest because being fast is awesome!"
"Your mane isn't really rainbow-colored!"
"WHAT?!" Rainbow Dash snickered, then fell on the ground laughing. "Really? Why do you think I'd be called Rainbow Dash if my mane wasn't really rainbow-colored?"
"It's a possibility!" Twilight retorted.
"Well, nope. I'm a natural rainbow." She picked herself back up and shook her head with another chuckle. "Got any other wild guesses for me?"
"You're... you're a colt!" Twilight tried.
"...No." Rainbow looked at her askance. "That'd be weird, Twilight. Where'd you come up with something like that?"
"Well, it's gotta be something!" Twilight burst out. "So far, I've talked with all of my friends, and they've all had some wild secret about how they change themselves based on their appearance!"
"Twilight, you already know my secret about my appearance!" She pulled out a copy of a Daring Do novel from one of the library shelves and tapped the front cover. "Remember? 'Reading is for eggheads?'"
"Right... you hide parts of yourself so others see you as cool." Twilight frowned and sulked.
"That not exciting enough for you?" Rainbow asked.
"Not really, no."
"Well, hey! How about I figure out your secret, then?" Rainbow said.
Twilight scoffed. "Don't be ridiculous. I don't have any secrets!"
"We'll see about that." Rainbow flapped about in the air as she pondered the question. "Hmm... major traits of Twilight... magic, books, Celestia... ah, let's start there!" Rainbow Dash landed and pointed at Twilight. "Why do you like books so much, huh?"
Twilight seemed bemused at this. "I've always loved books, Rainbow. They're so much fun, and there's so much to learn!"
"Any book?" Rainbow probed. "Any book at all?"
"Sure!"
"How about this one?" Rainbow flew up and grabbed the biggest book she could find. Twilight winced as it thudded against the ground. The Pre-Equestrian Tax Code and Civil Law Compendium; it was the largest tax code ever devised before Triponian created the much-simplified Ethicae Equestriae, a mere 15 pages of simple, non-jargonistic text. The Compendium, by contrast, was literally 100 times longer, and used so much legal verbiage that some of the terms literally had no modern translation, and nopony had any idea what they meant.
"Yup! There's so much to learn from the Compendium, even if it's just to know what not to do!" Twilight replied, still chipper as ever.
"Really? Ugh, of course you would say that." Rainbow shook her head and changed tactics. "Moving on. Celestia's your biggest role model, right?"
"Mm-hmm! Ever since I was young, I've wanted to become as great a mage as she is!" Twilight replied.
"Well, what about before that? What did you think of her, then?"
"Well..." Twilight strained to remember. "It was a while ago. But I'm sure I thought she was marvelous and kind, and that she always rules fairly yet justly."
"Uh huh..." Rainbow had a dangerous gleam in her eye that Twilight didn't seem to like. "And what about magic? Have you always wanted to be a mage?"
"Ever since I was little, I've emulated my ancestor, Vespers, in studying--"
"That's enough," Rainbow interjected. "Lightning round time!"
"Lightning round--?"
"Favorite food, go!"
"Uh, uh, steamed broccoli!"
"What do you think of Spike, go!"
"He's a good kid, keeps me stable, why--"
"How to be a good pony, go!"
"Follow the rules, stay out of trouble, don't--"
"Aaaaand got it." Rainbow Dash smirked and lazed back in her flight pattern. "I know your secret."
"Wuh-huh?" Twilight did a double-take. "How could you possibly know something just from that? I don't see a pattern."
"All right, I'll take it slow." Rainbow Dash leaned in and drew a line with her hoof. "What did all those questions have in common?"
Twilight didn't see it. "I... don't know. You asked about my favorite things, my system of morality, what I think of others--"
"No, no, not that!" Rainbow Dash shook her hooves and tried again. "Think about why you answered those ways."
"I don't know why I answered them that way!" Twilight replied. "That's just how I think!"
"Ugh! Who told you that reading was important?"
"My parents, probably, but--"
"And who told you that Celestia was a wise, kind ruler?"
"Probably my parents again, but--"
"And who told you that broccoli was delicious?"
"Nopony!" Twilight snapped. But then, she started to realize what Rainbow was getting at, and she cooled down. "But..." she mused, "my parents served it a lot, and I wouldn't want them to feel bad..."
"Okay, now tell me," said Rainbow, "what's something you like, something you know is good, that you decided was good recently?"
Twilight paused. "I'm sure I could think of something if I thought about it for a while."
"I'll save you the trouble." Rainbow touched down and looked Twilight in the eye. "You wanna know your secret? Here it is: you're a child."
"I... what do you mean?" But Twilight already knew what Rainbow meant.
"You're a child. Young, innocent, eager to please. You love books because your parents said you were supposed to, so you became the epitome of 'a pony who loves books' to maximize their love for you."
"That's not-- it couldn't be--!"
"You studied magic because your parents said you were supposed to. You love Celestia because you're supposed to. Everything you are is because somepony else decided it for you!"
"No, no, no!" Twilight stomped (like a petulant child, she noted) and turned away. "I don't want to hear any more of this!"
"But I'm not done." Rainbow flew over Twilight's head and landed in front of her. "You know everything there is to know because you read so much, but you don't think. You accept blindly what others tell you because you don't trust your own judgment." Rainbow Dash gestured with her wings over herself. "Me? I chose who I am. I see all the other possible ways to be cool, and I chose mine. But you? You're a child; you're not old enough to think for yourself."
"Please... no more..." Twilight gasped and put a hoof to her mouth. "No more..."
In an instant, Rainbow Dash's mood changed. "Oh my gosh, Twilight, I'm sorry! I was just trying to lecture like you do!" She threw a wing over Twilight and pulled her in. "I didn't mean to overdo it."
"Is that true?" Twilight asked, still sniffling. "Am I really just a child?"
"I dunno," Rainbow Dash replied, "I was just saying all that stuff 'cuz you asked me to. It sounded like it made sense, so I said it." Rainbow Dash scowled and kicked the floor. "I'm not very good at keeping my mouth shut."
"It's okay, Rainbow." She tried to smile, but it hurt to do so. "I know you meant well."
"Still, though." Rainbow thought for a while, then smiled. "You know, maybe you are still a child. But you're still cool in my book!"
This time, Twilight smiled for real. "You really think so?"
"Hey, you do cool magic, you're a princess; what's not to love?" Rainbow suddenly grew serious. "But if you're going to think you're cool, you have to think it because you think it. Not because I said so."
"Oh... right."
"Look..." Rainbow shrugged and looked away. "I'm really not the one to ask for lessons on maturity. I'm not much of a parent; I'm barely much of a sister. But if it were up to me, I'd say... get dirty!" She laughed and flew in a big circle. "Make mistakes, break the rules! You'll only find out who you really are if you break away from the expectations you've had put on yourself."
"Right." Twilight stood quietly for a few seconds, still trying to piece together everything Rainbow had told her. "So... what expectations did you have put on you?"
Rainbow suddenly put on the brakes, nearly crashing into the floor. She didn't seem to want to talk at first, but she managed to strain out, "You know how I dropped out of Flight School, right?" Twilight nodded. "That was why. And why you never hear me talk about my parents... that's why." Rainbow started to shake, almost imperceptibly. "I wanted to become the greatest flier in Equestria, so I abandoned everything and everypony in my old life. I... I chose who I am," she choked out. "I couldn't let who I was hold me back."
"Oh, Rainbow..." Twilight teleported over and embraced her. "That takes a lot of strength. I don't know anypony else who could do it."
Rainbow kept crying, though she tried to hide it from Twilight seeing. "I'm not strong, Twilight. I'm a coward."
"You are strong, Rainbow!" Twilight said. "And you're not a coward. Wouldn't I be the coward; I, who couldn't stand up against her parents?"
"...Maybe." Rainbow sniffed. "But I still ran away."
"You ran forward," Twilight replied. "And that's definitely better than standing still."
Rainbow Dash smiled. "...Heh. Well, maybe we can learn from each other, then, huh?"
"Yeah." Twilight smiled too. "We'll both keep pushing forward, deciding who we are, right?"
"Right." Rainbow Dash jumped back into the air and flew about in lazy circles. "I'll keep being the coolest pony in Equestria, and you... who do you want to be?"
Twilight thought for a moment. "I... don't know." Then, with a broad smile, she repeated, "I don't know! Isn't that exciting?"