At Valve, we like to play games made by other people, mainly because a) we don't have to make them, and b) they're generally more fun than ours anyway. In particular, games made by other people don't have Pyros named Eric Smith, who makes our collective lives miserable on a daily basis in playtests. (If you ever wonder why features like "Pyro now gets assists for airblasting enemies into environmental hazards" keep getting added to the game, thank Eric. Not content with killing us by just holding down W+M1, he persists in finding bold new ways to get points by any means necessary.)