The real problem of life in the material world is to solve the question of birth, death, old age and disease.
Srimad Bhagavatam 2.3.2-7,
Krishna, Krishna’s service and love of Krishna are the three great riches of life.
Madhya Lila 20.143
Life without love is useless and poor they say, Appoint me in thy service, Oh Lord with Love as my pay.
If at the time of death one can remember Krishna, one’s life is successful.
Srimad Bhagavatam 10.1.5-7,
One thing is certain; uncertainty of our life.