Why do we want happiness..

Why do we want happiness? The answer for this is very simple – because we are all fractions of God.
The Vedas say -

Chinmatram Shri Hareransham sukshma aksharamavyayam
Krishnadheenamitiprahur jeevam gyan gunashryayam

All the souls in this world are fractions of God. Like the ocean and a drop of water in that ocean. The drop
is a part and parcel of the ocean. Like a mountain and a small rock. That rock is a part of the mountain. Like the sun and a ray of light. The ray of light is a fraction of the sun. Similarly, all individual souls are fractions of God.

The Brahmasutra says -

 Ansho nana vyapadeshat

In the Geeta, Shri Krishna tells Arjun-

 Mamaivaamsho jeevaloke jeeabhootah sanaatanah
 

"Arjun, all living beings are my eternal fractions."

The Ramayan says-

Ishwar ansha jeev avinaashi

So, all the scriptures are saying that we are parts of God. He is the whole.
Now, we are parts of God, and God is an ocean of bliss.

The Vedas say-

Anand evadhastat anand uparishtat anandah purastat anandah pashchaat anand uttartah anando dakshintah 

anand evadam sarvam

There is bliss under God, above God, east of God, west of God, north of God, south of God, outside God, inside God, He is nothing but bliss.

The Vedas again say:

Raso vai sah

God is an ocean of bliss. It’s not that there is bliss in God. Rather, God is bliss. So, we are part and parcel of that ocean of bliss.
Now, it is the nature of each fraction to seek whatever it is a part of. This is a phenomenon of nature. For example, if you take some dirt in your hand, what is it a part of? It’s a part of the earth. So, what does it love? It loves the earth. But if it loves the earth why is it separate from it? Why doesn’t it fall back into it? That is because the hand is holding it. If the hand releases this dirt, it will fall back towards the earth. That is called the force of gravitation. The earth is pulling it towards itself. So, there is a law in nature that every fraction is attracted naturally to whatever it is a part of. All the rivers are flowing towards the ocean. Why do they flow towards the ocean? Because they are parts of the ocean. That river has been created from the ocean. The water vapor rose from the ocean, it formed clouds, the clouds began moving towards the earth and they showered rain onto the ground, that rain water collected into little streams, and those streams merged into rivers, and now that river is running. What is it running towards? The ocean. How long will the river keep running? As long as it does not merge into the ocean. So, since the river is a part of the ocean, it is naturally attracted towards it. And these flames of fire, they are not flowing towards the ocean, they are rising up. Why? Because the fire is a part of the sun. So, the fire is attracted towards the sun. Similarly, every living being, the soul, is a part of God and God is an ocean of bliss, so we are parts of that ocean of bliss and that is why we have this natural desire for bliss. And that is why whatever we do in this world is for the sake of happiness.