And Pinkie - being Pinkie - is on her way to another party. Marching along with a bundle of balloons tied to her saddlepack, she glances back over her shoulder at her hapless assistant.

"Come on, Fluttershy! The party can't start until the party supplies get there!"

...Maybe she shouldn't have agreed to let Fluttershy carry the majority of the load, but she did say yes!