An example of how un-happiness distances us from G-d is from the forefather Jacob. During the years that he inconsolably mourned for his supposedly deceased son, Joseph, G-d's Presence was not revealed to him. Only when he discovered that his son was alive and his sadness ended, did prophecy return to Jacob. Even for a righteous person free of sin, happiness was a prerequisite for receiving G-d's prophecies.

Even King David, whose biography is traumatic and tormented from beginning to end, tells us to “serve G-d with joy; approach Him with happiness.” King David had lots of reasons to be sad, angry, and resentful, but he realized that these emotions led him away from G-d. Being happy would actually draw him, and us, closer to G-d.

Indeed the Torah writes of punishment which will befall us, “because you did not serve G-d with happiness and a glad heart.” This verse is mystically interpreted to mean that the Jewish people displeased G-d because their actions were defective; they lacked the happiness that grants enthusiasm and motivation to fulfill divine service.

An analogy for the benefits of enthusiasm is of two sports competitors. One athlete is more physically fit and adept, but nevertheless lethargic and depressed. Due to his emotionally low state, the stronger competitor is outdone by his weaker but essentially happier opponent. Happiness causes the weaker person to win. Spiritually speaking, a happier individual is less inclined to be convinced to sin by his powerful evil inclination. His joy defeats negative forces and goodness prevails. So, in fact, a sad person is more inclined to sin and to distance himself from spirituality. While not Biblically forbidden, sadness is the root of much evil. But, as powerful as sadness is, joy is even stronger bringing a person to the highest levels of spirituality and connecting to G-d.

In addition to this, joy has the power to drastically improve one's life. When a person is happy and thereby elevated to higher spiritual levels, he can automatically cause negative aspects of his life to be transformed into positive ones. This is as the saying teaches, “Happiness breaks through (negative) boundaries.” So, by all means, BE HAPPY!