In life, at some point, we just have to admit that we can never fix certain things. It's best that we let them slip away. It suggests not negativity, it's a matter of being practical.
That's life. It's peculiar in its own way. Just like how happy songs can prolong one's depression to the point of no return and how depressing songs can emancipate one's soul that is long trapped in nothingness.
It's the sense of disappearance. To disappear in your own self, without having to justify anything, to anyone.