Most people don't realize the extent of self-sacrifice, both physical (financial, health, time, worry, etc.) & spiritual (e.g. their own learning, marriage, children) that rabbis, community leaders & general volunteers lose by serving their students & community. Rabbi's children especially suffer, resenting the high expectations from a very young age! Inevitably, some even rebel against religion or communal service, either consciously or sub-consciously holding "them" responsible for their lost time with their parent. Some rebel to gain their parent's attention. Rav Kook deals with these painful phenomena of literal Mesirut Nefesh (not just Mesirut "Guf"!) & the limits involved, explaining the importance of serving Am Yisrael= serving G-d.
We find various rabbis in rabbinic literature who built their spirituality through fasting and depriving themselves of physical pleasure. Rav Kook explains that this is like "shock treatment" or bitter medicine, which healthy people don't need. In Torat Eretz Yisrael, the Living Torah most applicable to the modern world, the approach of unity is to reveal the harmony between the physical and spiritual worlds. In Israel, where even the physical is spiritual and the atmosphere is Jewish, it's much more conducive to living a life of modern orthodoxy without the dangers of losing our proportions, priorities or getting influenced by western society. Accordingly Rav Kook explains the machloket between Rava & Abaye in Masechet Shabbat.