last checkpoint

Paulo Coelho, in his book 'By The River Piedra I Sat Down and Wept' once said, "There are some things in life are worth fighting to the end."
How does an end look like?
Is it when we try our best and it's not working?
Is it like we can't find any light in an endless tunnel?
Is it when we're tired enough?
What if we're just tired?
What if we're just wasting time?
Life?
Love?

I need to know whether you're worthy enough, or not.