Back when I was in the Christian mindset, serving the Lord had something to do submitting ourselves to the will of the Almighty God, whatever and whoever that might mean.
Life Processes, responsibilities. Throughout the course of each human's live we each have various responsibilities ("callings") that we are called to do to make life run smoother for ourselves and for others. When many people are young they don't want to be "saddled-down" with these responsibilities. Rather, they want to be free to do whatever they want.