Derpy burst through the doors to the back room of the post office.
"Sorry, I'm late!" she yelled. "Again!"
The pony she meet the day before was waiting for her.
"Well, you're not as late as last time, but..." she paused when she saw the cord that Derpy was holding. It was attached to a mangled clock. "What's that?" she asked.
"What's what?"
"That. In your mouth?"
"Huh?" asked Derpy, her right eye looking down as her left eye drifted upwards a little. "Oh." she said, dropping the cable. "I was having problems with my alarm clock this morning."
"I see." said the pegasus. "Here's your first set of mail."
A unicorn appeared, carrying a saddle bag wit her magic. She placed the saddle bag over Derpy's back.
"Whoa." she said, feeling the bag's weight. "Kinda heavy, ain't it?"
"Well, it's mail." said the pegasus. "Off you go."
"What?" asked Derpy.
"Go deliver mail."
"Now?" asked Derpy.
"Yes, Derpy. Now."
"Ohhhhhh." said Derpy. "Kay."
She left the back room and exited through the lobby.
She now stood in the streets of Ponyville. She looked around the town, not knowing where to start. She decided to start at the Library. She made her way over to the Ponyville Library and knocked on the door.
"Hello?" asked a pony, opening the door.
"Mail's here!" Derpy yelled cheerfully.
"Sorry, Derpy." said the pony. "I'm just here getting a book. No pony actually lives here."
"Drat." said Derpy, walking away.
She made her way to Carousel Boutique and knocked on the door.
"Yes?" asked Rarity, opening the door.
"Mail!" Derpy yelled cheerfully.
"Derpy..." said Rarity. "I believe the mail's supposed to go in the mail box."
"Dang it." said Derpy.
"But that's okay." said Rarity. "You're new. It could happen to anypony."
"Really?" asked Derpy.
"Oh, sure." said Rarity, rolling her eyes.
"What was that?"
"What was what?"
"You rolled your eyes." said Derpy.
"No, I didn't." said Rarity, quickly.
"Yeah, you did. Why?"
No reason." said Rarity. "You said I had mail?"
"Oh." said Derpy, suddenly remembering why she was here. "Yeah. It's... somewhere."
She sat the saddle bag down and rummaged through the mail. Rarity watched and waited patiently as the grey pegasus shifted mail around until she finally found one.
"Found it." she said happily.
"Oh, joy." said Rarity through a fake smile.
"Wait." said Derpy. "What's this place called?"
Rarity sighed. "Carousel Boutique."
"Oh... Sorry. Wrong one."
Derpy started to rummage again. Rarity leaned against the door frame and yawned.
"Find it yet?"
"Hang on." said Derpy. "Ooh. I think I got it."
She pulled out a medium-sized box.
"Yeah." said Rarity. "It does say Carousel Boutique."
"Sweet." said Derpy.
"Hey, Derpy." said Rarity, levitating the box inside the building. "Good luck at your new job. You'll get the hang of it."
Rarity rolled her eyes as she turned away.
"Hey." said Derpy. "You rolled your eyes again."
"No, I didn't." said Rarity, closing the door.
Derpy slid the bag back on her back and trotted away.
I'm such an stupid motherfucker for not reading the story's description and noticing it's written in simple skits.
Well, less one thing for you to worry about.
But then again: They are meaningless skits. You show derpy going to work and having a conversation with a clearly annoyed pony. And then? What happens? Even as a short, this needs more.
This chapter's issue: dialogs.
Yes, dialogs can be quite the pain in your ass if you're not careful with them. Even in a silly story like this, they have to carry some emotion to it
Have another copy/paste example:
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"Yes I did... but you see, Sweetie, even your big sister can be a big foal sometimes. I... know what you're going through... I even think that I am to be held responsible for that. I've always been so stern when it came to perfection that I sometimes forgot that it is something impossible to achieve. I think I might just have been a bad example for you. But I always told myself that you were smarter than me... that you wouldn't believe me and my senseless acting..." It was now Rarity’s turn to diverge her gaze from her sister’s. Small tears formed in her eyes, blurring her vision on the sides.
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That one bit I took from one of my chapters
Granted, this is an example of a sad/gloomy mood for a dialog, but I suck at writing silly things/comedy.
Remember: Emotion and character depth. Be careful not to break the character's established personality, or your story will be a massive OoCness that nobody will stand to read.