Overindulgence = a sluggish pace

Ever notice that when you drink some "adult" beverages or make bad eating choices that your running always suffers the next day? Either you choose to not to run at all or, like me, you force yourself to go run anyways and feel horrible, slow and like a ball of sludge on an endless uphill climb. It's just not enjoyable, people! So, why do we do it to ourselves?