The most important quality a Quarterback must possess to be considered a good passer is the ability to complete the ball, to be accurate. Many young QB's forget the most important body function that determines if you are accurate are your eyes. Doing anything athletically is a function of muscle memory and the eyes are the gateway to the mind. Your mind has no idea what you are asking it to do unless it sees what you want to accomplish. A QB must have "fast eyes". The ability to focus on the small spot he wants to throw the ball to so the mind can process the information it has been fed and thus have the muscles "remember" how to get the ball there.
The old baseball hitting adage of "keep your eye on the ball" is just as applicable to throwing it.
In anything we do, be it athletics, business or life if we keep our eyes on the target we have a much better chance of hitting our target or goal, or being successful.