The Torah forbids a person to eat Kodoshim when he is an Onen (the same day his close relative died) and the Sefer HaChinuch explains that Kodoshim are: ןַחְלֻשׁ ַהּוֹבָגּ the “table” of Hashem, and it’s not right to come to a Melech’s table with worries and big pains in your heart, like it says: קָשׂ שׁוּבְלִבּ ˂ֶלֶמַּה רַעַשׁ לֶא אוֹבָל ןיֵא יִכּ אסתר ד ב It is not proper to come before the king’s gate while wearing sackcloth. Not being B'simcha when eating Kodoshim is a form of disrespect to Hashem. This is a new understanding of the greatness of being B'simcha! It’s Kavod Shamayim when you show that you are happy in Hashem’s beautiful world, and it’s actually a chutzpa and a Zil'zul in His Kavod when you kvetch and become sad and you complain.
No wonder Simcha is such a burning issue; and even your body dislikes sadness and anger, etc. How important it is to make Simcha and Bitachon a high priority in your entire Avodas Hashem.
All Hashem wants is to see that we are trying to work on Simcha and Bitachon, as the Sefer HaChinuch says that a person has to be: ִמ ְשׁ ַתּ ֵדל (to try) to act like Hashem, and be full of Rachamim and be nice to others. The more you act with Rachamim, the more you bring goodness to yourself and to the whole world. A person can’t be like Hashem Mamash, who tolerates so much Avoda Zara and: ִר ְשׁעוּת wickedness, and yet He gives and gives unending pleasures to all of His creations. But the Sefer HaChinuch says לֵדַתְּשִׁמ! Just try!
