Life.. how should we look at it? - part 1

I have been asking this question to myself and to many people around me.. Why do we exist in this world?.. But, I've never got a convincing answer till date! Lol.. so if any of u people reading this think you've got an answer, please help me out.. though i've got my own perspective about things.. Its like when i ask you.. 'what job do u wanna end up doing in your life if you can choose what ever you wanted?' what answer are you gonna give me? If u end up saying 'a minister.. a business tycoon.. an actor.. a doctor.. a software professional' I would just consider you to be crap.. I don't deny the fact that i would most probably end up being one of the above.. haha.. but the question was.. what would you choose if you had your choices.. Well.. i feel we need to give our heart and soul to this earth.. 'Mother Earth' if i have to show more respect..! We are nothing when we compare our size to that of this planet.. One bloody comet hits the earth.. and its gone.. whoosh.. like that..! And here we are.. sitting and thinking about money.. cars.. movies.. and all possible nonsense..! We have to change ourselves at some point of our lives..! One act of random kindness.. and that would do a great deal of good!..