Life is short. We know this intellectually, but we rarely act on it. We fill our lives with bullshit, and assume there'll be plenty of time tomorrow to do all the things we don't get done today.
In one of his Letters From A Stoic, Roman philosopher and statesman Lucius Annaeus Seneca urges us to be more grateful for the time that is given to us, by living as if each day was our last and treating every morning as a bonus:
"Let us go to our sleep with joy and gladness; let us say: I have lived; the course which Fortune set for me is finished. And if God is pleased to add another day, we should welcome it with glad hearts. That man is happiest, and is secure in his own possession of himself, who can await the morrow without apprehension.
When a man has said: "I have lived!", every morning he arises he receives a bonus."