"Cigarettes don't understand the bitterness of life" means that cigarettes can't eliminate the difficulties and pains encountered in life. "Spirits can't dispel the troubles in the world" means that spirits can't dispel all kinds of troubles and troubles in the world.
This sentence expresses that everyone in the world will have unspeakable suffering and need to face it bravely. At the same time, it also reminds people not to rely too much on cigarettes and spirits to escape from reality, but to face up to the problem and actively seek solutions.