Ever play a game online (cough...Gears, Call of duty...) and wonder how the flying fuck some of these idiotic design choices even made it past testing? Well this is why. There's a world of difference between playing in a controlled environment where lag is a non-issue, and playing against a cheating douchebag seeding 10 gigs of Naruto episodes on their dial-up connection.
I propose a drastic change in the way games are tested and demoed. Copies of every game to be tested should be given to an entire class of 15 year olds to play at home. You'll find out in a damn hurry everything that can and will be exploited in your game.