(2004/5764) The Mishna Berura (583:5) states that one should
be especially careful not to become angry on Rosh
Hashana. He explains that in addition to the “great sin” of
becoming angry throughout the year, one should control
his anger on Rosh Hashana in order to serve as a Siman
Tov (“good sign”) for the upcoming year. Instead of
becoming angry, one should be content and trust in
Hashem, along with engaging in Teshuva and good acts.

The Real Simcha of Sukkot by Ely Winkler

Purifying Mikveh by Moshe Zharnest