Why?

I sometimes ponder over thoughts which could possibly keep me engaged for the whole day. Sometimes the thought hits me that why do I think so much? But then I feel this is just an indication of an active brain. There is a vast ocean of thoughts which are in my head, sometimes they flow smoothly but at times they flow furiously. Why is it that I get frustrated and wish to see no tomorrow but then I hope that it is the sunshine of tomorrow that would put an end to my frustration? Why do I have to cry out of happiness and why can't I laugh my sorrow out? Why is it that we need to think positive all the time and take the negative as a shock? Why can't we think negative and accept the positive as a bonus? Well my questions need to be answered and I think as I move ahead with life and gain wisdom through my experiences I could find answers to these questions which are crowding my head!