Gratitude and Mortality

Is the purest form of gratitude a complete awareness of mortality? In order to reach the deepest levels of gratitude is it necessary to become conscious that every single experience is ending? That every single sight, sound, and touch is constantly ending?

Would it be possible to invert all expectations about life, existence, and appearances so that the only expectation is of non-existence? Of absolute Nothingness? Why should there be anything at all? Does there need to be anything at all? How does needlessness correlate with gratitude? What if you needed nothing, not even to survive? How would your experience of reality change? Could you become conscious that nothing is needed, guaranteed, or taken for granted? That the fact that anything exists at all is a miracle in itself?

How could you reach the deepest appreciation for every single moment? Is its capacity in direct relation to your consciousness of mortality/Nothingness? Is it in re-contextualizing the evaluative framework for appreciation so that rather than basing it on self-generated expectations and biases, every transient instant is perceived as a flickering appearance from nowhere? Is the key in stillness – both in the actual act of pausing to immerse your attention in something, and in the knowledge that that stillness itself is the only constant?