Rainbow Dash, Destroyer of Pies

Secrets and Pies gave us a good look at the relationship between Rainbow and Pinkie. She's always been one who seemed to have little time for Pinkie's antics and now we see that she's been lying for a long time to spare Pinkie's feelings. While it can smooth things over in the short-term, it's not a good idea in the long term, as she found out in this episode.

You can get the SVG vector file at Derpibooru.