We are in this world for a purpose. We have to look for the reason to be in this world.

I have found my purpose. I was greedy, self-centre, selfish, smoker and othrers but now I am helping disadvantaged people (single parent, handicap and people looking after sick relative) to work from home. If we could make a living and same time help others to survive. Is so much meaningful. Now I realised the statement your quoted below

Lao Tzu preached that we exist to sacrifice for other beings, and that is the purpose.