Physicists are one of the more interesting breed of scientific creature. It seems that a good physicist just can't leave well enough alone - it's not enough that a ball rolls, they need to understand WHY the ball rolls. And what force caused it to roll. And why it rolled as far as it did. And what would happen if it had been a bigger ball. And what if it was in a vacuum. And what if was rolling on the Sun. And... Look, it's a damn ball, OK? It rolls. Move on already!