Rabbenu Yonah wrote in Shaarei Teshuvah (1:31): “When a person breaks his desire regarding permitted things as well, then his nefesh will succeed, and this middah will be sweet for him, for it will uplift his mind and he will overcome [his physical urges] and be stronger....” One who succeeds in breaking his passions and desires is zocheh to be in control of his nefesh, and this is a very sweet, beloved thing. Our whole avodah in this world is to live in an uplifted way, and a person feels true satisfaction when his mind is able to overcome his physical desires.
I was zocheh to see Rav Gershon Libman zt”l eating in a unique way: He would mix cornflakes into every dish he ate in order to ruin the taste of it, and then he would eat happily!
The nazir is sanctified to Hashem because he distances himself from permitted things in order to uplift himself in avodas Hashem. And this is indeed our job – to become accustomed to stopping ourselves by, among other things, limiting our indulgence in pleasures that are technically permissible.
I heard from Hagaon Hatzaddik Rav Mordechai Weinkranz zt”l that the main focus of avodas hamussar is self-control.
The nazir wears a crown like a king, he refrains from impurity of a dead person just as the kohen gadol does. In the Shulchan in the Mikdash there was a frame and also a golden crown around it, and from here we learn that in the physical realm as well, when we set boundaries, we are zocheh to the crown.
One who lives with serenity and joy controls himself, and one who controls himself is zocheh to menuchah and serenity.
