Gemara: One who "immerses" his food in water will not come to intestinal problems.

Ein Ayah: It is proper to become aware that in the matter of spiritual sustenance, as regarding physical food, there must be a proper balance. We have already stated that bread is a metaphor for halacha. It is dry, but it is also the foundation of our nutritional sustenance. However, to do its job, it requires water to enable it to be digested and spread throughout the body as part of the life-giving blood stream.
So too, in the spiritual realm, aggada (hinted at by water) serves to reveal the good effects that the knowledge of and involvement in halacha has. Actually, any true knowledge, even if it is "dry" and shares nothing with the "spiritual logic" that straightens one’s personality and uplifts the soul, helps complete the spirit. The positive impact is actualized when the knowledge is accompanied by the spiritual wisdom and fear of Hashem. These can reveal the way the knowledge makes spiritual impact and purifies a person’s characteristics.
This is all the more true regarding the directly holy knowledge of Torah. Aggada complements the intensive study of halacha, enabling one to extract the desired results from it. Without the study of aggada, which enables the learner to taste fear of sin and love of Hashem, the "dry knowledge" would remain "undigested" and cause "intestinal illness." There is such a phenomenon in the physical world, and, through its metaphor, in the spiritual world.
It is important to find the right balance between the areas of Torah study. [We skip over Rav Kook’s technical dealing with the gemara’s various commentators regarding the metaphor]. It is possible that someone who is already a giant in Torah and has "filled his stomach" with practical knowledge will choose to elevate his spirit by focusing primarily on Divine concepts that are at the root of the words of aggada. It is these that are the goal of man’s self-completion and the road that leads him to salvation from pain and the evil inclination.

The Limits of Remembering Death
(based on Berachot 6:30)

Gemara: One who is used to eating lentils once in thirty days prevents askara (a painful, lethal disease). However, he should not eat lentils every day because it causes bad breath.

Ein Ayah: This teaches a moral lesson because lentils are a classic food for mourners. In the spiritual realm, there is reason to periodically remind oneself of the fact that death is part of life. Fear of punishment is also a healthy thing, as it dampens one’s spirit in a manner that distances him from haughtiness, which causes him to forget Hashem.
However, one should use this tool of rebuke only periodically. On a daily basis one should use the higher level of spiritual encouragement, based on love of goodness and righteousness, according to the pleasantness of Hashem. This is because over-reliance on the simple but harsher tool of fear of punishment causes sadness or craziness and puts bad ideas into the heart. A person can be complete in his views and characteristics only when his spirit is happy, which widens the mind and raises the heart in fear of Hashem. A subdued spirit lowers a person, and the words of Torah will no longer be sweet to him. The metaphor of bad breath is appropriate because in that state one cannot taste the food’s appeal, and he will be missing the spiritual sense of a good smell. The same idea applies in the spiritual realm. Therefore one should not overuse the harsh rebuke of remembering death to fight the evil inclination.