Why is Nature predisposed to indulging in vices? We hold on to that which gives us pleasure, even though it subtracts from our physical life. A system seeking life most pertinently would not engage in activities that negate it, so life doesn't seem to be the top priority for our system. In looking to Physics for an answer, it's deductible that the pleasure vice grants is actually excitement, which is energy — motion.
That means that vice puts the system into a state of instability; why would we seek instability? Instability, as the motion of energy as physical matter, is simply energy transfer, meaning that energy cannot be concentrated in one place for too long. If energy is concentrated, it "brews", it creates an extremely volatile center which is another kind of instability. Therefore, is it possible to say that instability cures instability? That there is no stagnant state of balance, only ever a balancing act. There must always be motion within our Universe system.