Question

If life was all about HAPPINESS and SADNESS then why are we even born on EARTH?
(THINK PRACTICALLY AND ANSWER)

Answer 1

ABSOLUTELY NOTHING .. 

I would like to share a link to a brilliant answer for reference purpose. 

We have entered this world with no sole purpose. Human life merely sustains 70–80 years and this period, as compared to construction and destruction of this universe is nothing.

We know that the Big Bang was the reason for the creation of this world and the whole universe is expanding ever since.

Answer 2

If life was all about HAPPINESS and SADNESS then why are we even born on EARTH?
Because to prove that we can do anything hugely
We need to achieve something
Our life need both sadness  and happiness otherwise our life will become boring.......