This seems to be the answer to Rabbeinu Bachya. One of the greatest motivators in the human is enthusiasm. That enthusiasm is based on a value system. If I value money, I will be driven to pursue it, and the acquisition of it will bring me great joy. If I gain a deeper perspective on life, then I experience elation, knowing that my net worth in the World to Come is growing at an incredible rate. My investments are paying back in spades. That excitement is one of the most powerful motivating forces, equal even to kavod. With it, a person can reach great heights. Without it, a person’s avodas Hashem can become stale and lose its potency.
Ultimately, joy is a great force that both allows a person to enjoy his short stay in this world and propels him to achieve the greatness for which he was created.
