Because he was a cruel prankster who effectively tortured the ponies for who knows how long, then spent thousands of years trapped in stone, tortured them again, got trapped again and then… reformed, just like that? You don’t write off all that so easily.
Celestia: Wait a minute, I AM an adult!
Okay. That works.
Well, it is a pun, but based off another pun.
Oh. I thought that it was a pun because Discord was blue in an episode.
http://www.youtube.com/watch?v=axHe_BVY_9c
Was that meant to be a pun?
He’s totes trying to win her back :3 #OTPHe’s trying to annoy her is all. He’s Discord. He was made to annoy everypony.