Even if he has some desires, one engaged in the service of the Lord is never frustrated. Those who approach the Supreme Personality of Godhead with desires for material enjoyment are called sakāma, and those devotees who have no material desires for sense gratification but serve the Supreme Lord out of spontaneous love for Him are called akāma. Sakāma devotees are divided into four classes – those in distress, those in need of money, the inquisitive and the wise. Someone worships the Supreme Lord because of bodily or mental distress, someone else worships the Supreme Lord because he is in need of money, someone else worships the Lord out of inquisitiveness to know Him as He is, and someone wants to know the Lord as a philosopher can know Him, by the research work of his wisdom. There is no frustration for any of these four classes of men; each is endowed with the desired result of his worship.
Ref >> Srila Prabhupada Vani.