It is true that by practicing restraint of the senses by the yoga system one can get relief from the disturbances of desire and lust, but this is not sufficient to give satisfaction to the soul, for this satisfaction is derived from devotional service to the Supreme Personality of Godhead. — Srimad Bhagavatam, 01.16.35.
Whatever devotional service we may have, we do it for seeking the shelter of the Lord, not for our mental or physical enjoyment.
By rendering devotional service unto the Personality of Godhead, Sri Krishna, one immediately acquires causeless knowledge and detachment from the world.
The child cries to have toys, but one who can cry for the Lord in love is certainly successful in the line of devotional service.
Devotional service to Krishna is the chief function of the living entity. There are different methods for the liberation of the conditioned soul Karma, jnana, yoga and Bhakti but all are dependent on bhakti. — Sri Caitanya Caritamrita, Madhya lila, 22.17.