"The real perfection of life is whether by your actions, Krishna is satisfied. That is perfection. You don't consider of your personal victory, defeat, loss or gain, or distress or happiness. Therefore Bhaktivinoda Thakura has sung that: 'When I work very difficult task for Krishna, 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."
(Srila Prabhupada Lecture, London, September 4, 1973)