The average human lifespan is absurdly, terrifyingly, insultingly short. Here's one way of putting things in perspective: the first modern humans appeared on the plains of Africa at least 200,000 years ago, and scientists estimate that life, in some form, will persist for another 1.5 billion years or more, until the intensifying heat of the sun condemns the last organism to death. But you? Assuming you live to be eighty, you'll have had about four thousand weeks.
-Oliver Burkeman, Four Thousand Weeks: Time Management for Mortals