In your understanding, what is the role of joy in religion?
Chassidim, especially Lubavitcher Chassidim, believe that joy has an important role in religion. While praying, the more joy one can experience, the closer the supplicant is to G-d, and the more divine sparks he (or she) can reunite with G-d. This is why singing, dancing, and other joy-producing activities are acceptable while praying or, at the very least, acceptable to be done by them, their conservatism notwithstanding.
As far I can see, this is the only case where joy has an actual religious/theological purpose, an importance in the Divine Plan.
Is there anywhere else where this may be so?
WRS - neranena bishuatekha.