Bhaktivinoda Thakura has sung that: "When I work very difficult task for Krsna, that difficult task becomes very happiness for me. That difficult task becomes very happiness for me." That is the standard of happiness. In the material world, there is duality. In the absolute world, there is simply happiness. There is nothing else. Just like when Krsna is going to Mathura, all the gopis become very, very distressed, crying. But we cannot understand what is the happiness of that distress. That we cannot understand from this material point of view. That is greatest happiness. When the gopis were crying in separation from Krsna, that is greater happiness than meeting Krsna, than meeting Krsna. This is Krsna philosophy.

>>> Ref. VedaBase => Bhagavad-gita 2.36-37 — London, September 4, 1973