The Purpose of Existence

Lot of times have i thought about it. And this is one of the "yet unanswered" riddles for me. Why do we exist. What is the purpose of our existence. Quoting H2G2... is it so that we may find the ultimate question whose answer is 42?? Well well... no kidding. But seriously thinking. Why do we exist. Why do we live on and on. Why do we hang on to life like a desperate being. Maybe because if we die, no purpose may be fulfilled. But who knows. And this is not confined to us human beings only. What bigger purpose is fulfilled by the existence of animals, the water bodies, the Earth, other planets, our galaxy or even the whole universe.
I work in an IT Company. When i go to work i see a lot of people going to work with me. Lot of opened shops on my way in which people sit waiting for a customer. Lot of kids going to school. What for?? To become like us or better than us. But what would that fulfil. The development of human kind. But again why is it that important?? And anyways what kind of development are we talking about?? The people work for their family. I work for the survival of my family. Our next generation would be doing the same. And their kids will again follow and this would continue. Would it change anytime. When will it stop? Or if it is necessary then why is everyone's survival necessary. Ending it on a comparison which most will not find to their taste: What's the difference in us(human beings) and animals? They too work(hunt or whatever) for their food just like we go to our daily workplaces to earn our bread.
I'll be continuing in my next post. Till then: Happy Hunting