Reason #2: You get to relax.
1. We start out babbling, me, me, me, want food, want comfort. We formulate longer-term desires to achieve, to get things, to matter.
2. If we're lucky, we gradually learn to take in the outside world. We begin to meditate and hear the demands of the self, and acknowledge the reality of other people, to not push ourselves forward so much. We get some freedom from the cravings of the small self.
3. We live long enough that life keeps knocking us with the fact of death and we figure out that we are one small golden blip on the great black river, and all those words don't matter so much after all.
So there. You get to relax your ambitions. That's reason #2.