The first ten million years were the worst. And the second ten million: they were the worst, too. The third ten million I didn't enjoy at all. After that, I went into a bit of a decline.
Not my words, but a quotation or two for Terry H's digestion, from Marvin the paranoid android, penned by Douglas Adams.
http://www.youtube.com/watch?v=q4P3pvKmbsgTechnically, as matter and energy can only be transformed, not destroyed, our component bits are as old as the universe and will always be around in one form or several others. You could say our current existence is but a brief transient moment, but our actions, their ripple effect consequences and our physical sub-parts are immortal.
All good stuff to consider when staring into the night sky round a campfire in the woods and discussing the meaning of life. (Its 42).