another example:
if a receiver beats his man off the LOS and is running down the field with a step on him man.if the ball is placed in front of him where all he has to do is catch it and keep on running he will look pretty good.
if the ball is underthrown and the receiver has to stop and jump to try and catch it with the defender all over him , odss are it could turn into a drop or even pick.
same example but lets now add a safety in the middle of the field.
you throw that ball to the side line in front of the receiver and it could be a catch and TD
you throw that ball to the inside where the safety is and you will end up in a heavy contested pass which most likely will end up in a pick,
heck the timing of when you throw the ball can make a huge difference.
usually a receiver is open for a brief second after he makes a cut in his route.
if the ball is already on its way before he comes out of his cut then it will look as he is wide open which ofcourse will make him look good.
you throw that ball to late and the defender has a chance to recover and thus will have a better shot at making a play on the ball and well people will complain receivers are never open.