How not to launch a single-player game

I have lost count of the number of MMORPG launches I participated. Given that sort of experience, I would say that the launch of Diablo III was par for the course: Login servers overloaded. Strange error messages including "you don't own a copy of Diablo III" regardless of whether you bought the game online or retail. Lack of official information from Blizzard. Pretty much what you'd expect for any big MMO launch.