When Pinkie Pie wakes up one night, she has trouble laughing. She remembers how Granny Pie taught her how to laugh, long ago when she still lived on a rock farm.
I wrote this because the Pinkamena story from "The Cutie Mark Chronicles" didn't match up with "Giggle at the Ghostly." If the writing style seems disjointed (at least, I think it does), it's because I was trying to evoke Pinkamena.