Yom Kippur is commonly regarded as a day of solemnity and regret. While solemnity and awe are important on Yom Kippur, it is not required to feel miserable over sins and to mourn inadequacies. Of course, it is a good idea to sincerely regret what has occurred in the past, but this regret should take the form of bitterness rather than sadness. According to Chassidic philosophy, when one thinks of past misdeeds one should feel a sense of bitterness rather than sadness. What is the difference? Bitterness spurs us on to action and inspires us to change. When we feel sadness, however, it drags us down and gives us a feeling of worthlessness. When we are literally “down in the dumps” it is almost impossible to get up and do anything. This is why bitterness is the right attitude and sadness is avoided, especially on Yom Kippur.
What about crying over sins? Isn’t it a good thing to show Hashem that we truly feel bad about our past mistakes? There is a time to feel regret during certain types of prayers or before retiring at night. But according to the Shulchan Aruch, the code of Jewish Law, one should awake with the eagerness of a lion, and should approach his or her daily life with alacrity. Depression and morbidity are not virtues, but can drag a person down. It is said that the evil impulse causes a person to sin not because it relishes the misdeed, but because it can do more spiritual damage causing a person to feel depressed and bogged down in guilt over the sin that it can accomplish through the sin itself.
Although we are supposed to “afflict ourselves” in a sense on Yom Kippur, since we refrain from food, drink, leather shoes, washing and marital relations, this is not a day filled with regret and mourning like Tisha B’Av. On Yom Kippur, we are like angels and we do not need these ordinary physical things, since the day itself is on a very high spiritual level and brings the world up with it. Angels do not to eat or to wear leather shoes, and it is on this day that we are on a higher level than any other day of the year and have the greatest spiritual potential. Therefore, the holiness of the day should not be squandered on sadness but should be focused on a rectification of our souls and the maximizing our potential for the year ahead.