Grooming takes a beating during these three weeks. The Ashkenazi custom is to avoid getting haircuts during these three weeks. It has always been interesting to me to observe what a big deal haircuts are in Jewish Law. It defines the Sefira period; it defines Chol Hamoed; it defines mourning itself.
It defines dignity itself. Halacha states that the king had to have his hair cut every single day. Cohanim had to have a haircut no less than once every thirty days. The Cohen Gadol once a week. And the Talmud says that it was a very unique haircut, known only to certain professionals! Level Seven in the earlier list of Jerusalem’s levels of holiness was prohibited to any Cohen who had long hair!
The past fifty years saw segments of western civilization rebel against the perceived strait-jacket of appropriate hair stylings. It’s interesting to note that letting their hair grow long coincided with many other moral shifts.
Books can be written, and I’ll assume have been written, about Hair and Civilization. But for now, the focus is on mourning. The implicit assumption of Halacha is that the sensation of mourning leads one to care far less about his coiffure. His life has been shattered; outer appearance takes a back seat. Our sense of personal dignity takes a back seat when we are confronted by the loss of our nation’s dignity, and God’s dignity.
We are reverse-engineering the concept here. We want to replicate the sensation of mourning, so we adopt the practices of someone who is in that frame of mind, in order to enter that frame of mind!