While Dave is the real professional when it comes to napping, Jack is no slouch either. He is one of the great amateurs of our time. He just doesn't want to put in the energy to compete globally on the level that Dave does.
But Jack will have a friendly napping duel with Dave from time to time. This is good practice for Dave, much like the great tennis pros typically practice with other very good tennis players. It keeps Dave on his game.