Much as I like Princess Celestia being Sunset Shimmer’s mom/mother figure and it’s probably actually true in canon given some comments, it’s also funny to me, especially stuff where Celestia has raised her from a really really young age, because it changes the whole introduction Celestia gives in the first Equestria Girls movie from just
Celestia: That was Sunset Shimmer, she was a former student of mine that disappeared when I refused to give into her demands.
to
Celestia: That was my baby, Twilight. She was my whole world. I watched her take her first steps. I taught her everything she ever knew. She made me believe that I could be happy again. She called me “mom” once and I cried for a week straight. A piece of me died the day she went through that mirror and it’s a piece I’ll never get back. Here’s a baseball bat with nails in it, Twilight. Go teach that bitch a lesson for breaking her poor mother’s heart.