"Nothing is more irrational than spending our lives trying to fend off mortality when no one has ever escaped that fate." (Westen, The Political Brain)
You could just as easily say, "Nothing is more irrational than going to the movies when no one has ever seen every movie ever made."
This is a great example of what I call the Woody Allen Fallacy - the idea that an infinite amount of life is valuable, but a finite amount isn't. Trying to fend off your inevitable demise is as rational as you can get, because dying sooner is worse than dying later.