Friendship is Dragons

Rarity: An owl! Think of all the interesting roleplaying that could happen.
DM: No.
Pinkie Pie: Adding him to the party would be such a hoot!
DM: No.
Rainbow Dash: I didn't know there were other playable races. Hey, where can I find the Griffin race?
Luke: Page 19 of this book.
DM: No.
Fluttershy: My Animal Empathy feat works on him too, right?
DM: No. Wait. I mean... Luke cannot play an owl!
Rainbow Dash: Why not?
DM: It doesn't fit the setting!
Luke: Well, I did have another character concept in mind. Don't worry. This one's a pony.
Rainbow Dash: So this thing here improves flying speed?
Luke: That's right. Had to take the flaw Big Eater to afford it, though.
DM: Hahaha... No.