Our Gemara on Amud Beis references an idea that the first three days of mourning have a separate significance. Moed Kattan (21b and 27b) speaks of this as a time for “crying” and extra grief. More so, Shulkhan Arukh (YD:394:1) codifies this a halakhic requirement to refrain from excessive mourning and to limit the “period of crying” to the first three days. Pele Yoetz (“Bechiyya”) also speaks of the importance of being sad during those three days, and not allowing oneself to be comforted, but then to not overstep beyond the three days of intense grief. Though this does not mean a literal ban on crying but rather a ban on excessive bereavement and sorrow, it still may seem odd for the Torah to regulate human emotions. If one is in distress, how is it humane or realistic to expect a person to change or control those feelings?

But actually, many parts of the Torah regulate human behavior and emotions. We are commanded to love God (Devarim 6:3), when to rejoice (ibid, 16:14), and even when to be intimate with our spouses (Shemos 21:10)! 

Rav Hirsch (Horeb 320) speaks of the importance of the Torah setting boundaries for human emotions such as grief, so as not to be carried away. A way to understand this is that humans do best when they have certain boundaries. We can realize intuitively that a driver will drive better just by seeing the guardrails. Knowing what is expected. and theoretically healthy, allows for coping and adjustment. Of course this is with the proviso that these guidelines not be experienced as oppressive thought control.

Maase Rokeach (Moed Kattan 1) notes that Tractate Moed Kattan is both about mourning and the intermediate holidays, times of grief and of joy. Both Chol Hamoed and Aveius are often bounded by a seven day period and certain of their laws are derived from the same verse (Amos 8:10.) The Baale Musar encourage a state of Hishtavus, which is best translated as Equanimity. Sefas Emes (Bereishis Chaye Sarah 26, Devarim Re’eh 4, and Shemos Vaera 11) speaks of accepting all that comes from God with a  open and positive reception. He says, too much joy and investment in the material blessings somehow also invites and empowers the negative forces. Baal Shem Tov (Iggeros HaBesht) makes a play on words: The phrase “שויתי ה׳ לנגדי תמיד” “I constantly place God before me”, can also be translated as, “I encounter God with equanimity.” (שויתי = I make equal ) Likewise, Chovos Halevavos (Shaar Yichud Hamasse 5) also speaks of the importance of taking all that God brings with a state of equanimity. This is a productive and healthy human state, and therefore not surprisingly, many religions have a special word to describe this state (see Wikipedia “Equanimity.)

As an aside, the English word, “copacetic”, which in many dictionaries is listed to be of unknown etymology, would seem to come from “Hakol B’seder”, as the word “Boss” would seem to come from “Baale Bayis”, or in Yiddish diction, “Baleboos”. In any case I say, “All right, Boss, “Hakol B’Seder.”