Why do people see Christian morality as oppressive rules instead of a guide to human happiness?

Created by God, in the image of God, the only way humans can experience true happiness and satisfaction is by forsaking the illicit pleasures of the world and following God's will and commandments. Following these rules actually leads to a true and lasting happiness, rather than the fleeting and temporary pleasure of sin. And all sin leads to is an ever-increasing desire for ever-diminishing pleasures. God and the spiritual life is the only solution, and then all the rest falls into place, and the pleasures of the world, used in their right context, are made even more pleasurable.