Great visual perception is one of the hallmarks of a successful playmaker.  Knowing what to do with the ball before it arrives is a critical skill that must be developed by young players.  Because soccer is a continuous, flowing sport, the conditions around a player are always changing.  Having your "head on a swivel" is essential to assessing the changing landscape of pressure and open space.  Check out this video of one of the greats as he is constantly assessing his environment.  For a more in-depth understanding, read this article on the secret to vision.