American football is so slow.
You know what really makes American football slow? The commercial breaks. Between drives, timeouts, quarters and kickoffs there are almost always 2 minutes of commercial time. I live in Europe, so I have to record the late games. That enables me to skip all those breaks with a few button presses every 10 minutes or so.
The four downs encourages a running game because it's a safe play and you can normally get a couple of yards so it's a quick running play followed by a time out to reset the ball and then almost 40 seconds to start the next play.
Not quite. The clock only gets stopped when a player runs out of bounds, otherwise it keeps running, plus the 40-second play clock starts immediately. There are a few other situations where the clock gets stopped, but that has nothing to do with the kind of play you are executing.
I've watched a few Super Bowls and it's terrible how long they take to play. Especially the last couple of minutes. The four downs allows teams to throw the ball away to stop the clock. It seems like the last two minutes of a game can take a half hour to play with the time outs and other ways to manipulate the clock. None of it is illegal but it makes for an extremely boring game.
Again, not quite. They don't "throw the ball away to stop the clock". That would get them nowhere. Time gets stopped when the pass is incomplete or the ball carrier runs out of bounds. It is true though that the last 2 minutes can take up 30 minutes. That's because both teams try to save the timeouts for precisely those last 2 minutes. If a team has no timeouts left or wants to save one, the quarterback can throw the ball into the ground right behind his center ("spiking") to stop the clock as well. Assessing penalties stop the clock temporarily, too.