Maybe she has a tremendous capacity to concentrate on a task. Maybe she's just "laser focused." Maybe she is "mission driven."
Or maybe Gracie is a Black Lab's Black Lab. There are a few nouns we don't use around her...food and ball. O-u-t-s-i-d-e may be spelled slowly. Otherwise, we get the usual reaction...hyperkinesis.
Where there is ball, there is no other object. Food can sometimes distract her from ball, but as soon as food is gone, ball returns and drives away all other objects again.
It's sorta cute at first, until she shoves a slobbery tennis ball into your crotch as you sit at your desk. Then it loses its cuteness rapidly.
So if you should ever have an infestation of tennis balls, Gracie's your dog.