Is there any insight to human folly?

"My life is like a memento mori painting from European art: there is always a grinning skull at my side to remind me of the folly of human ambition. I mock this skull. I look at it and I say, "You've got the wrong fellow. You may not believe in life, but I don't believe in death. Move on!"

This quote relates to the folly of someone who rejects belief in God and the afterlife. Mortality is only for unbelievers.