Celestia had come to Twilight's castle expecting to see how Starlight Glimmer's friendship lessons were going. But, in her mind, she knew that her night was about to be wasted.
Heat season was always the worst for Twilight, especially since coming to Ponyville. However, thanks to her accident with the Want It, Need It spell and her clones, she has a great outlet this season. The consequences, however, are big.