I'm guilty of this. Often to make points or to deliberately shake people's foundations, I'll speak of the perfection in horror or the non-reality of death. Life even: I've denied life, I've denied self, I've denied a lot -- normally, as said, to shake foundations or make points.
This trick is used by the great Tzu's as well as by the uneducated armchair philosopher me. And the greats use it to fine effect -- beyond this toying though is the unity of opposites and not the negation.
The trick in negation is to deny life and death, genuine happiness or sadness, being out of line with Tao or being enlightened, by pointing to how opposites only exist due to one another and so cannot exist alone.
This is well used by the masters and well abused by myself, but this itself is too only one side of a coin. Beyond this game of comparing or negating the sides of a dualistic way of reasoning is the uniting of the opposites.
Life and death, self and other, good and bad, can be negated, but better still can be united into the great oneness. Loving life and fearing death, wishing for happiness and despising sadness, along with all of the other dualities, these can be embraced with content when truly seen to be, not either or, but something just beyond our minds, that which is both.
You can check out Ta-Wan's other musings here.