The words of Torah should be as fresh to you as if you first heard them today (Rashi, Deuteronomy 11:13).
Excitement often comes from novelty, but novelty is exciting only as long as it is new. Someone who buys a car fully loaded with options may feel an emotional high, but after several weeks, the novelty wears off and it is just another vehicle.
Spirituality, too, suffers from routine. Human beings may do all that is required of them as moral people and observe all the Torah's demands in terms of the performance of commandments, yet their lives may be insipid and unexciting because their actions have become rote, simply a matter of habit. The prophet Isaiah criticizes this when he says, "Their reverence of Me has become a matter of routine" (Isaiah 29:13). Reverence must be an emotional experience. A reverence that is routine and devoid of emotion is really no reverence at all.
Thus, the excitement that is essential for true observance of Torah depends upon novelty, upon having both an understanding of Torah today that we did not have yesterday and a perception of our relationship to God that is deeper than the one we had yesterday. Only through constantly learning and increasing our knowledge and awareness of Torah and Godliness can we achieve this excitement.
Life is growth. Since stagnation is the antithesis of growth, it is also the antithesis of life. We can exist without growth, but such an existence lacks true life.