Logic Of Life

As we know life if full of Happy and Sorrow.
How a living being achive this two?
Its very simple.
All this Happy and Sorrow are of chain reaction.

Example:

First person-A do a mistake by manhandling some one, and this mistake is cleard by other person-B, But remember that human being has no right to excuse mistakes done by human. Means person-B has done a mistake. Then person-C clear mistake done by person-B and now Person-C has done mistake..................... thus this process goes on.

There is no Limit to New Life and No Limit to Happy and Sorrow.