Hearthstone was announced at the Penny Arcade Expo in March of 2013, but Blizzard seemed to know it had a hit on its hands long before that moment. Dustin Browder, lead designer of StarCraft 2 and now game director of Heroes of the Storm, sent this e-mail to Hearthstone lead designer Eric Dodds in September of 2012.

"Internally, Hearthstone's always draws crowds," Dave Wilson, Blizzard's "Branding/social media guy" tweeted with the above image. "The Blizzard museum displays a classic email between game directors..."

The rest, of course, is history. We can only hope the game was never banned in the office.