We are like fish out of water. Just as a fish cannot be happy unless he is in the water, we cannot be happy apart from the spiritual world.
The happiness in serving is the happiness that material nature cannot impede because we can always serve in some way or the other.
For a person who has suitable shoes on his feet, there is no danger even when he walks on pebbles and thorns. Similarly, for one who is always self-satisfied there is no distress. Indeed, He experiences happiness everywhere.
Through the popularizing of hari-kirtana, or the sankirtana movement, the brahminical culture and ksatriya government will automatically come back, and people will be extremely happy.
Purport on Srimad Bhagavatam 7.2.11
Simply by chanting the holy name of Krishna – Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare – a devotee of the Lord can approach the supreme destination easily and happily, but this destination cannot be approached by any other process of religion.
Purport on Bhagavad Gita 12.6
There are many in this world, and specially in India, who think wealth & power can make a person happy. For them I say, I am comming right from that point, down the road, there is nothing!