After my sitting last night, I came away with the feeling that zazen (or at least my zazen) has a "silent struggle" quality to it. There seemed to be a resistance to non-thinking or not identifing myself with the thoughts that arose. It was as if the mind or ego constantly wants to impose itself back into the "scenery". It gives my sittings a sense of struggle or a "still activity" to them.
I'm just interested in what more experienced sitters might have to say.