Why keep the commandments?

Why do I need to listen to God? The reason I keep the commandments is only because of reward and punishment. Reasons like He revives every moment, He created the world, and gratitude do not convince me. As a believing Haredi yeshiva student, I questioned why I need to keep the rabbinic and strict commandments and laws without justification. After all, the reason I keep Shabbat, tefillin, and kashrut is reward and punishment. The very fact that I am a yeshiva student who keeps the minimum, in the equation of reward and punishment, top 5000, (according to an equation that was calculated, the world is divided into 5000, in the first degree), so why do more than the minimum?? And why keep laws without justification, or laws that I disbelieve in justification? And moral laws, theft, honoring parents, are subject to my decision, according to the degree of my morality, so why do I have to keep them?