All of those external factors which we need to interact with in order to survive and to guarantee the continuity of our species can produce addictive pleasure, addictive enough to motivate us to move that ass and do what has to be done with our lives.
Eating is enhanced with the sense of taste, a taste that’s only used when we eat or when we shouldn’t eat. The happiness felt through the pleasure in your taste buds when you enjoy every bite of that delicious meal, and the relief of letting all the impurity and left overs out of your body, it can be pleasurable sometimes that you actually don’t mind taking a shit one more time.