Sunset Shimmer knows a magical path to slapping Twilight upside the head! She used to be Princess Celestia's student, but quit because all she did was levitate cake from one place to another. Also, her final form is clearly that of a troll, proving that she did everything for the lulz and was merely brainwashed to think otherwise by an unseen blast of magic from one of the Princesses, who were butthurt over having been out-trolled by some insignificant ho.
Like all epic trolls who troll trolls, Sunset Shimmer should be celebrated. She is also the only remotely redeeming thing about Equestria Girls, so this in itself is worth noting.