If it's the last thing I do

"If it's the last thing I do." We rarely hear that expression, do we? I wonder why not? Perhaps it's the stuff of stories. You know, the protagonist with a cause that come hell or high water, will fight for it to the death.
There's the 'bucket list' that is popular these days; places you have to go to before you turn to dust.
But that isn't quite the same is it?  It's not the same as contributing to something..grand. Okay, I'll admit that sounds so earnest.. so noble.
But when it comes down to it, as many things are with me these days, 'the last thing I do' is becoming an imperative saying for me to live by.
I mean it. If not now, then when?
I keep thinking to myself- I'll be walking along, or I'll be doing the dishes or whatever, and then it hits me like a block of wood to the head; I could die. I will die.  So what am I contributing to this world? What am I doing? What am I fighting for?  Big, scary questions maybe but they demand answering.
With equal weight, I am asking myself, what am I getting out of life? What wonders am I perceiving? What ideas are wowing me, moving me? Am I in touch with the mysteries that surround me?
If today were my last day on Earth, how would I be living it?