We have no right to tell the person, who is at the preliminary stages of his development and still desires bodily pleasures, wealth, power, fame, and knowledge, that all of his activities are worthless and base, and that he should aspire to attain spirituality. If we tell the person at the wrong time that this world is worthless, we simply drive him to depression and hopelessness, in which case he will have nothing to hold on to while moving from one pleasure to another. He will not be able to advance.
Hence, it is said: “Do not put an obstacle before a blind man,” meaning one should not tell the person that his life is insignificant, transient, and imperfect. Like a child at play, he needs all these “playthings.” Billions of people living in the world gradually advance towards the purpose of creation.
http://www.youtube.com/watch?v=Ea_iZ3NfwSU