For I, Hashem your G-d, am holy. Hashem created us in His image, and at the same time provided us free will to choose our path in life. We have been granted the opportunity to emulate His ways, in order to build a stronger connection to Him. The highest level a person can reach is to use these tendencies in the proper manner. Mastery over one's inclinations does not mean to hinder or do away with them.
Any natural propensity is neither good nor evil in itself.
These powers are given to Man to give him the ability to accomplish the will of G-d. The Torah gives us positive aims and negative limits, showing us how to use our inclinations for the will of Hashem. Holiness is not acquired by just the performance of morality to the letter of the law, but rather it is attained when one uses all of his tendencies for the service of Hashem and goes beyond the letter of the law. Since every person has been granted different gifts from the Creator, we can all serve Hashem in our own unique way. By using one's talents and inclinations to serve Hashem, a person builds a stronger spiritual connection and ultimately attains holiness.