The kind of good I feel that feels better than the others seems of a different kind. Deeper, more as though it resonates on a deeper level than simply liking something. Gives a sense of inner joy, really. Maybe this sense is something that is built in; you sense when your internal state is least incongruent, least conflicted.

I don't hold much for perfect "unassailability". I suppose nothing we feel or know is totally unassailable. Uncertainty is part of our existence; I find it quite tolerable to not be "certain". We do the best we can.