I present you all an audio reading of one of the earliest GrimDark stories of the fandom:

The Severing of Friendship by RagingSemi

(Story not on FimFiction.net)

This reading has been featured on Equestria Daily.

If you need persuasion, consider that the success of this story inspired a two major GrimDark sequels by A Fistful of Apples, the success of which allegedly inspired Sergeant Sprinkles to write Cupcakes.