Holiness of the Sukkah
It is good to be careful not to speak empty words in a Sukkah, as the Sages taught that the Name of Heaven rests upon the Sukkah, as it rests upon the festival offering (Talmud: Sukkah 9a). And it is known that our holy Rabbis taught that the Sukkah is filled with Divine Names, as it is known that the Gematria of the word "Sukkah" is 91, which is equal to the combination of the Name YKVK and ADNY, therefore one must be careful in the Sukkah not to desecrate its holiness.
Similarly, one can understand from the story that the Rebbe taught about the Maggid of Trisk, who waited for a long time at the door of his sukkah before entering. He said the reason is that in the High Holidays liturgy we see that a person is compared to a clay vessel, and the Talmud teaches that it is forbidden to bring a clay vessel into a Sukkah (Talmud: Sukkah 29a). He only entered the Sukkah once he felt the humility of a broken heart, because the Talmud teaches that the way to purify a clay vessel is by breaking it. (Mishnah: Kelim 2:1).
(Sefer Orchos Dovid - teachings of Rebbe Dovid Mattisyahu of Biala, zt"l - p. 87)