It is a a kind of Positive (Big "P") that holds, dances and flowers as all the small human moments of positive and negative, smiles and tears, safety and distress. One need not even feel happy all the time, and there is a certain "Positive" as one sits broken hearted next to the casket of someone loved. It is a Peace that holds peace and war, all the round and sharp pieces of life. No need to feel merely "peaceful" all the time. My Teacher, Nishijima, and countless other Buddhist teachers, say that Buddhism is a positive, even "optimistic" philosophy (despite all the talk of "suffering", the real focus is not that ... but "Liberation"). When we drop thoughts and selfish judgments and appraisals, what remains is ... not an empty nihilistic nothing, not directionless chaos, not greyness, not darkness ... but peace, freedom and fertile possibility! Not an empty hole ... there is Wholeness. Even a Wholly Holy Wholeness.
An old Zen saying ... "Every day is a good day" ... 日々是好日 ...
There is something about this reality that is Positive, not negative, not positive, going in the direction all needs to go, so Beautiful ... even though ugly sometimes. It is a Beauty encountered when we drop all small human judgments and demands of "beautiful" (small 'b') and ugly. Thus, we sit in the Wholeness of Shikantaza.
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So hard for us to realize that this is Buddha, that is Buddha, quiet is Buddha, noise is Buddha, coming is Buddha, going is Buddha, thoughts are Buddha, absence of thoughts are Buddha, peace is Buddha, anger is Buddha, stillness is Buddha, movement is Buddha, alive is Buddha, dead is Buddha. Buddha is not simply silence and stillness. We simply sit because, in the day to day clutter and confusion of our minds, a space for a bit of silence and stillness may help us better realize such fact when we drop all the cutter and confusion for a time. But the point is not that the silence and stillness of sitting is "where its at", because our way is to "non-find" (because always present in the bones even though rarely seen) a Silence and Stillness (Big "S") that --is-- and always has been the clutter and silence and peace and chaos and confusion and stillness. Both peace and anger are Buddha, but anger blinds us to such fact because so divisive! As well, peace can hide Buddha too if we think that is the only place Buddha is to be found.
The eye and everything the eye sees is Eye all along. True Peace is peace and tumult and all the round and sharp pieces of life.
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The True Piece of Shikantaza is a Peace so Peaceful, a Beauty so Beautiful, that it sweeps in and out the peaceful moments and the sharp pieces of life, the beautiful and ugly to the human eye. The Silence is so Silent, that it hold the chirps of the birds, breeze in the branches, cannons and bulldozers.