Personally, Celestia has had few surprises — oh, there were a few: the unexpected return of her dear sister, Discord, the Crystal Empire's, and Tirek's escape. But most things, she finds, are nice and calculated... until now.
A few years after Luna's return it seems that Equestria will finally know an era of peace and appears to be on the verge of a new renaissance. Ponies are happy. Luna is recovering. Celestia is miserable.