Many people justify their participation in a variety of behaviors by calling them "natural." However, the following quote from M. Scott Peck reveals the flaw in those arguments:

Calling it natural does not mean it is essential or beneficial or unchangeable behavior. It is also natural to defecate in our pants and never brush our teeth. Yet we teach ourselves to do the unnatural until the unnatural itself becomes second nature. Indeed, all self-discipline might be defined as teaching ourselves to do the unnatural.