Seriously, a lot.

(Now with a Spanish translation by the generous SPANIARD KIWI!)

Princess Celestia tires of constantly being surrounded by decorum, deference, and formality, and decides to take a day off from being Princess. But visiting Ponyville incognito is harder than she expects. Will she be able to fit in and make friends without blowing her cover?

When Twilight visits Celestia's private hall of stained-glass windows, each bearing the image of a long-gone friend, one in particular catches her eye.

Who was this pony?

Why was she so important to Celestia?

And why does she look so familiar?

There is now a Spanish translation of this story, courtesy of Spaniard Kiwi