Joy is like a butterfly that comes and sit on our hand but can never be grasped or held. Instead Loving kindness practice, remembering to be grateful to self and others for every little boon and even for difficulties, consciously letting go of grudges help displace the sludge that builds up around the heart and keeps joy away.
According the Upanishads and the Shaiva and Shakta Tantras, Ananda is unison with God. Same association of joy with divine experience in Sufi poetry, in the Kabbalah, and writings of Christian mystics can be found.
Ananda (The Bliss)
When Mudita deepens, and it becomes our entire field of experience, we find ourselves in touch with the most profound level of joy: Ananda (Bliss) but in reality bliss is too ordinary to convey what Ananda in reality is.
Ananda is ecstasy, the rapture, a joy that comes up on its own from the very depths of the universe and connects us instantly to the vastness of pure being. Ananda is the divine power in the form of happiness. When someone touches it, he knows it he has touched the deepest level of reality.