The spirit soul can be happy only in the association of the supreme living being, the Personality of Godhead, and nowhere else.
Srimad Bhagavatam 3.2.11,
One has to learn tolerance in the face of dualities such as happiness and distress, or cold and warmth, and by tolerating such dualities become free from anxieties regarding gain and loss.
Bhagavad Gita 2.45,
There is no peace or happiness in our worldy life. Circumstances create turmoil and annoyance.
To the degree we cultivate the spirit of selfless service, to that degree we’ll actually find bliss in life.
"Accept Krishna as your friend. You will be happy." This is the message of Krishna Consciousness.
Civilization and Transcendence,
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.