The more we are happy in Krishna Consciousness the more we become purified.
Actual joy is a product of the spiritual nature. It spontaneously manifests when the living entity begins to love God.
That procedure which in the beginning may be just like poison but at the end is just like nectar and which awakens one to self-realization is said to be happiness in the mode of goodness.
When we understand our relationship with God then we all will be happy. It is an essential factor for establishing peace in the world.
Joy can only be experienced when we offer our love to Krishna.