Why do we hurt?
Because we want to keep something.
Why do we want to keep something?
Because we like it, we love it.
Why do we like it, why do we love it?
Because it gives us happiness, it gives us pleasure and satisfaction.
Why do they do so?
Because they are a temporary fillings in our heart's emptiness.
Why does the heart have emptiness?
Because emptiness is a fundamental attribute of human life.