The Ibn Ezra says that the reason why a Nazir has to bring a Korban Sh’lamim is to show his contentment and joy since he was Zoche to fulfill his vow. Look how an Oved Hashem has to always be happy over his accomplishments in Avodas Hashem. You don't just make a Kabala (resolution) and keep it. You make a special party thanking Hashem for our success! Human nature is to kvetch over Aveiros, but being happy over Mitzvos isn't always so common. Kvetching over sins is the Yetzer Hara; not the Yetzer Tov! Believe it or not!
Your happiness level for your mitzvos should be higher than your regret for your aveiros.
I was told that in Novardok they made a big party when they kept their Kabalos (resolutions). Notice how a Nazir has such a fancy name, as if he has a crown on his head. ָנ) ִזיר מל' רֶזֵנ ( When you call yourself a Melech, you feel good about yourself! And growing long hair symbolizes your superiority to other people who don't control themselves! RSRH Zatzal says that hair symbolizes the body's insulation against the outside world, since it protects the skin against the elements.
By letting the hair grow, the Nazir creates a barrier against the outside world. Besides the: לִיַא ram (i.e., a large sheep) he brought for a Shelamim, he also brought a ֶכּ ֶבשׂ sheep for an Olah, and a ַכּ ְב ָש ה sheep for a Chatas. The Ramban says that the Chatas is for not doing more Nezirus (self-control). Notice how the Chatas is just a sheep and the Sh’lamim is a more expensive: לִיַא ram. Make sure your happiness level for your Mitzvos is much higher than your regret level for your Aveiros.
Look how much Simcha and dignity and good feelings surround the Oved Hashem; being called a Melech and feeling superior to others, with his long hair and with bringing an: לִיַא ram (i.e., a large sheep) for a Sh’lamim to show his Simcha for completing his Kabala (resolution).
This is how a Yid should work on himself; surrounding himself with Simcha and feelings of superiority (in the right way). No wonder the Tochacha says: בָבֵל בוּטְבוּ הָחְמִשְׂבּ ˃יֶק˄ֱא 'ה תֶא ָתְּדַבָﬠ אֹל רֶשֲׁא תַחַתּ זמ חכ אבת that Tzaros come from lack of Simcha, like when you don't appreciate your own greatness, and you aren't always partying and praising Hashem for being a Ben-Torah, or a Baal Chesed, or a Baal Yissurim which is sometimes the biggest Ma'ala. Like it says by the Brachos: תוּיִּמֲמוֹק םֶכְתֶא ˂ֵלוֹאָו גי וכ יתקוחב you'll stand upright with confidence.
Like Dovid HaMelech sang half a night after half a night of learning Torah and, R’ Zundel of Salant Zatzal explains that the singing was in thankfulness for the Torah he had just learned. Every Yid should always be in an: וּנֵקְלֶח בוֹטּ הַמ וּנֵרְשַׁא “How fortunate is our lot!” mode, and if he isn't, then it's a sign that he isn't learning the right Mussar.
Notice how when a person gives away a Gashmiyus Simcha (שונא בבל חמשי ןייו) by becoming a Nazir, he is trading it for a Ruchaniyus Simcha, by being called a Melech (Nazir), and eventually bringing a beautiful Korban Sh’lamim and feeling good about his long hair which lifts his status among people.
So every time you look away and watch your eyes, or refrain from Lashon Hara, or control your anger, etc. you should know that you are trading this Gashmiyus pleasure for a much better Ruchaniyus pleasure.
