Chauncey Billups when he played was probably one of the best basketball players at using the one dribble freeze fake shot. What this basketball drill is simulating is that you have shot faked your defender, got them off their feet, taken one dribble past them for the pull up shot, and either they have recovered to try and block the shot, or another defender has stepped up to try and block the shot. The freeze fake shot allows the defender to fly by, and then opens up a shot.
Another great way to use the freeze fake is to draw a foul on the defender that has left their feet. Make sure though that you do not lean to far out into the defender or the referee will not call the foul, because you initiated the contact.