Ah, but Pinkie Pie -- the series began with the effective ending of that relationship. Though I still remained Twilight's teacher in many ways, the time had come for her to fly on her own and learn not from books or me, but from life itself. What is interesting is not an unchanging fixture of the world, but the growth and development of the ponies who live on that world. You and your friends.

The sun is only interesting when it fails to rise, after all. Or inhabits the sky with the moon at the same time, apparently.