I am getting read to teach Twelfth Night and was struck by this reference to music in the teachings of Rabbi Nachman of Breslav:
“Presaging the hit song of Summer 2014, Rabbi Nachman of Bratzlav famously taught, “It is a great mitzvah to be happy always.” In fact, Rabbi Nachman further observed, a century ahead of his time, sadness can lead to illness; poetically, he explained that this was because the body needs ten different kinds of music to survive, and all are threatened by gloom. Yet Rabbi Nachman himself could not uphold this mitzvah. Throughout his entire short life, he struggled with depression – latter-day diagnoses have ranged from bipolar disorder to more serious mental illness – as well as with physical ailments. It is an impossibility to be happy always.