I've had this (often drunken) conversation many times, I think mortality is fundamentally ingrained in not just the human condition, but the fabric of our universe. Without the finality of death, life seems to lose its meaning. Not only do we need to die, we are compelled to die, we should die. This memento mori makes every day, ironically, worth living. One of my favorite verses from the Bible is Job 1:21, where he somehow reconciles this tragic finality with trascendent faith:

    “Naked I came from my mother’s womb,
        and naked I will depart.
    The Lord gave and the Lord has taken away;
        may the name of the Lord be praised.”