"If I do not think of Krsna, My impoverished mind will die within a moment like a fish out of water. But when I see Krsna's sweetly smiling face, My mind and eyes are so pleased that My desire for Him redoubles." [Antya 17.59]
The pursuit for happiness in this material world in like a fish trying to survive out of water.
Srila Prabhupada write in this connection, "Everyone in the material world is engaged in all kinds of political, philanthropic and humanitarian activities to make material life happy and prosperous, but this is not possible. One should understand that in the material world, however one may try to make adjustments, he cannot be happy. To cite an example I have given many times, if you take a fish out of water, you can give it a very comfortable velvet bedstead, but still the fish cannot be happy; it will die. Because the fish is an animal of the water, it cannot be happy without water. Similarly, we are all spirit soul; unless we are in spiritual life or in the spiritual world, we cannot be happy. That is our position.Everyone is trying for that spiritual realization. But we do not know. Therefore, we are trying to be happy here, in material conditions. We are becoming frustrated and confused. Therefore, we have to withdraw this understanding that we shall be very happy by making adjustments to this material world. Then Krsna consciousness will be effective. " [TYS 3: Beyond the Laws of Nature]