The limit to your existence.
Noone knows how long or short it is.
Noone can predict when you'll reach your end of the rope.
If you waste your life on dwelling on the past,
You may never make it to the bottom of the cliff that your rope hangs from.
If you waste it on building towards the future,
You'll hit the bottom too fast and too hard.
Do not think of how you got to the top in the first place.
You'll only find that you put yourself there be fault.