Dual line kites change all that.
If you pull the right line the right half of the sail is pulled towards you and the kite turns to the right, or clockwise, and if you pull the left line the kite goes left, or anticlockwise. Very simple and intuitive, but in fact the aerodynamic principles involved are less simple and have been the subject of lengthy discussions on rec.kites. It is also possible to control the speed of the kite, by pulling both lines together - the harder you pull, the faster it goes, and if you allow the lines to go slack by throwing the hands forward, the kite stalls. Dual line flying was first popularised by Peter Powell with a dual line Eddy or Malay type of kite. Originally a dihedral design, modern versions, especially cheap polythene ones with sails printed with Disney characters or similar, are normally bowed by wind pressure.