Tisha B'av 2023 The Necessity of the Day
The Frierdiker Rebbe related:

The Holy Ruzhiner (Chassidic master Rabbi Israel of Ruzhin, 1797-1851) rejected all feelings of sadness, even of bitterness. So his chassidim would engage in all sorts of practical jokes on the Ninth of Av (in order to mitigate the sadness of the day). They would throw burrs at each other. Then they conceived of the following prank: they opened a skylight in the roof of the study hall and dropped a snare; when someone walked into the study hall, they would yank on the rope so that the snare fastened itself around him, and pull him up to the roof.

It happened that the Ruzhiner himself walked in to the study hall. Those who were up on the roof could not see clearly who was coming in, so they pulled him up. To their dismay, they saw that they had pulled up their rebbe! As soon as they recognized who it was, they let him down.

Cried out the Ruzhiner: “Master of the Universe! If Your children are not properly observing Your 'festival', take it away from them!”
Is the Holy Ruzhiner's response a rebuke of his students or approving their behavior?
Chassidic teaching differentiates between destructive sadness ("atzvut") which leads to depression and inertia, and a constructive "bitterness" ("merirut") that leads to soul searching and corrective action.
When have you experienced "atzvut" and when have you experienced "merirut"?

הִנֵּה יָקָר גְּנּוּחֵי וְנֹהַ מֵאִישׁ יִשְׂרְאֵלִי, כִּי הוּא שְׁלֵמוּת הַחֶסְרוֹנוֹת, כִּי עַל־יְדֵי בְּחִינַת הַנְּשִׁימָה, שֶׁהוּא הָרוּחַ חַיִּים, נִבְרָא הָעוֹלָם, כְּמוֹ שֶׁכָּתוּב (תהילים ל״ג:ו׳): וּבְרוּחַ פִּיו כָּל צְבָאָם; וְחִדּוּשׁ הָעוֹלָם יִהְיֶה גַּם־כֵּן בִּבְחִינַת הָרוּחַ, כְּמוֹ שֶׁכָּתוּב (שם קד): תְּשַׁלַּח רוּחֲךָ יִבָּרֵאוּן וּתְחַדֵּשׁ פְּנֵי אֲדָמָה;

(ג) וְהוּא גַּם כֵּן חִיּוּת הָאָדָם, כִּי חִיּוּת הָאָדָם הוּא הַנְּשִׁימָה, כְּמוֹ שֶׁכָּתוּב (בראשית ב׳:ז׳): וַיִּפַּח בְּאַפָּיו נִשְׁמַת חַיִּים; וּכְתִיב (שם ז): כֹּל אֲשֶׁר נִשְׁמַת רוּחַ חַיִּים בְּאַפָּיו; וּכְמוֹ שֶׁאָמְרוּ חֲכָמִים: אִם תֶּחְסַר הַנְּשִׁימָה – תֶּחְסַר הַחַיִּים.

(2) See how precious is the sigh and groan of a Jewish person. It provides wholeness [in place] of the lack. For through the breath, which is the ruach-of-life, the world was created. As is written (Psalms 33:6), “… and by the ruach of Adonai's mouth, their entire hosts [were created].” The renewal of the world will also come about by means of the ruach, as in (Psalms 104:30), “You will send Your ruach —they will be created; You renew the face of the earth.”

(3) This [ruach] is also the vital force of human life. This is because the human’s breath is their life-force. As is written (Genesis 2:7), “He breathed into his nostrils nishmat (the breath of) life,” and (ibid. 7:22), “All in whose nostrils was a nishmat (breath of) ruach-of-life.” Regarding this, wise ones said: To the extent breath is lacking, so is life.

(ה) וְהָאֲנָחָה הוּא אֲרִיכַת הַנְּשִׁימָה, וְהוּא בִּבְחִינַת אֶרֶךְ אַפַּיִם, דְּהַיְנוּ מַאֲרִיךְ רוּחֵהּ, וְעַל כֵּן כְּשֶׁמִּתְאַנֵּחַ עַל הַחִסָּרוֹן וּמַאֲרִיךְ רוּחֵהּ, הוּא מַמְשִׁיךְ רוּחַ־הַחַיִּים לְהַחִסָּרוֹן, כִּי עִקַּר הַחִסָּרוֹן הוּא הִסְתַּלְּקוּת הָרוּחַ־חַיִּים כַּנַּ"ל, וְעַל כֵּן עַל־יְדֵי הָאֲנָחָה מַשְׁלִים הַחִסָּרוֹן:

(5) And sighing is the extension of the breath. It corresponds to erekh apayim (patience)—i.e., extended ruach. Therefore, when a person sighs over the lack and extends their ruach, they draw ruach-of-life to that which they are lacking. For the lack is in essence a departure of the ruach-of-life. Therefore, through the sigh, the lack is made whole.