Football is the ultimate team game.  It is one of the most popular sports in the world today.  Football is also the most physically demanding sport played today.    You must be strong physically and even stronger mentally.  Quarterback is the toughest position on the field to play and  perhaps in all of sports.  You have to be able to understand what the players on your team are doing and you have to know what the other team is doing on defense.  A quarterback has to read the defense, find the open receiver and deliver a throw to a teammate with a defender covering them.  A quarterback has to do all of this within seconds   before a 250 pound opponent hits him.  Who are some of the Greatest Quarterbacks of all time?  Is there any one thing that makes them great?