Every man is hungry for spiritual happiness. Therefore they are not satisfied. They are trying to gratify their senses in so many ways, but still they are not satisfied, because actually he is hungry. Just like this child crying. Mother is offering something, but he's still crying. That means he is asking something which the mother cannot understand. Similarly, the dissatisfaction of the modern world means that actually everyone is hankering after spiritual happiness. But nobody is offering. And even if it is offered, they cannot understand. They do not take it.

From Srila Prabhupada's lecture on Bhagavad-gita 2.40-45 — Los Angeles, December 13, 1968