In Buddhism, the idea that all phenomena will arise, abide and cease, is all pervasive - whether it be this moment, the toaster in your kitchen or the physical body you currently inhabit. I am no expert in the field of Buddhist philosophy but I do know that this concept, this reality of impermanence, is applicable and helpful in all aspects of life. When we accept that all things will end, whether they are happy things or sad ones, we can begin to step away from clinging, which ultimately causes suffering.
When I remember that I am mortal, that I could die ten minutes from now, I feel a strong sense of liberation. I no longer permit myself to fret over trivialities and instead rejoice in the freedom that impermanence grants. In a happy moment, we can fully surrender, knowing that this moment will end and never happen again. In times of sadness or tragedy, we can remember that this too will pass, permitting ourselves the space to feel our emotions fully.
On the mat, remembering the reality of impermanence is paramount.
While taking your fifth breath in Warrior Two there is no need to fight the sensations, no benefit from wishing the moment to pass because regardless of the mental drama, it will pass. Sinking into the asana fully will be far more rewarding than rebelling against it. Instead of fuelling the panic by clinging to attractions or aversions, watching the mind and letting the thoughts be breathed away will bring about a stable sense of equanimity. Yoga helps us to learn how to exist in each moment fully, ultimately releasing resistance against any current situation.
So thank Shiva, sing an OM and raise a Hallelujah for the beauty of impermanence. It all will pass: this moment, this sandwich, this life. Find the bliss, sink in and don't wish it away.