2 dumb fishermen

2 dumb fishermen decided to rent a boat on a lake for their favorite sport. After fishing for 4 hours at various places around the lake with no luck at all they decided to try one more spot before calling it quits, Suddenly things started to happen, and they caught their limit inside of twenty minutes. paul said, (Hey we should mark this spot, so next time we will know where to come,) Jim says good idea, and he took out a can of spray paint and made a large X on the floor of the boat....to mark the spot.... With that paul says, why did you do that, now anyone who rents this boat will know where to fish.