An explainable sadness

So, whenever I "level up", feel the discomforts of the little deaths going on within because replacement is happening, they include sadness of the mourning variety. It occurs to me that maybe that's because we get so attached to things. We form a habit of beliefs, perceptions, reactions, feelings associated with. These are familiar. We feel security in the predictability. We feel less than because of ______, _____ comes, as "we know it always does" and so we are as usual prepared and handle it accordingly, thus believe it self empowering: we can predict the future! It's familiar. It fulfills expectations. It is our "friend" and we "love" it.
So, we mourn the loss of our friend which brought us so much trauma and leave the false sense of security found in familiarity when we upgrade. We set sail on the sea with what feels like no rutter, no sail, no horizon. Even when we discover we are the rutter, the sail and the horizon, we are letting go of those that got a us through and arrived at yesterday. And maybe justifiably so! They got us so much further than the day before, exposing greater horizons on the way! So maybe I shall embrace the mysterious feelings of sadness I couldn't explain. The sadness is an acknowledgement of the greatness of what we have been. I am aware in my sadness. I love awareness- I let it go so often, lol. My sadness is thus gratitude. It is a coming home and I can feel at home in it.
Thank you.