I think the closest we can come is through the absolute love of another where our thoughts transform from selfish desire to ones of selflessness. When we lose that, perhaps it hurts so badly because in that moment, we glimpse paradise only as it's moving away from us, and only then are we cognizant of its loss.

The most disturbing theory I've heard yet on the nature of existence is that everyone of us is the same person having a different dream, which begs the question, which one of us is the one dreaming, and which of us is the dream?