Sukkos is called: וּנֵתָחְמִֹש ןַמְז the time of our Simcha. If the very name of the Yom Tov is: ןַמְזוּנֵתָחְמִֹש the time of our Simcha, then its very essence is Simcha, and you need to go all out for the Mitzva; not just to be “Yotzei”.
The truth is that every Shabbos and Yom Tov is a day of Simcha, but those times have other names. Like Pesach is called: ןַמְזוּנֵתוּרֵח the time of our redemption. A big person told someone that he should avoid eating with people who cause him stress, because on Pesach you need to be extra relaxed and feel free ) ֵח ירוּת( .
The Gr”a speaks about the difficulty of not having any worries on Sukkos, which isn’t so much of a problem on other Yamim Tovim. Although it’s always a big Inyan on Shabbos and Yom Tov but on Sukkos it’s a whole new dimension. Every seven years, there is a Mitzva of Hakhel. Everyone would gather in the Bais Hamikdash, men women and children, and the Melech would read from various selections of Mishneh Torah, i.e., Sefer Devarim.
When was the time for this Mitzva? The Passuk says it is to be done during Sukkos, during the year following Shemita. Why specifically then? We can suggest that since the Melech reads Sefer Devarim which is full of sharp Tochacha, it must come with a super happy background.
So only Sukkos which is total Simcha (וּנֵתָחְמִֹש ןַמְז), and following Shemita, right after a year of total relaxing Bitachon, is the time for Tochacha. Similarly, we read Koheles on Sukkos, since Koheles (which is heavy Mussar) can only be during: ןַמְזוּנֵתָחְמִֹש the time of extreme Simcha. So be careful that before you start “Mussar-izing”, to make sure you’re loaded with Simcha.
Before Getting Involved in Mussar Make Sure You’re Loaded with Simcha
Some people may have to spend a lifetime with working on lots of Simcha and loads of learning Sifrei Bitachon, besides writing down their Hashgacha Pratis stories and the Maalos of themselves and their situations. It’s brought down that Shlomo HaMelech first wrote Shir HaShirim, and later Mishlei, and last Koheles. Notice how first comes an unusual amount of Simcha (Shir HaShirim - the song of songs) before we can have Koheles.
In Novardok they were experts who knew how to learn tough Mussar and become Davka happy since they were trained to love Mussar. Yet, I heard that R’ Nekritz Zatzal once needed to learn lots of Chasidishe Seforim for a period of time, since at that point he needed a boost in Simcha.
