Love, for example, is something most of us desire - in some way, shape or form. For some, it is manifested in the physical - the way in which we interpret it to mean more than it is. For others, love is something spoken, regularly, a linguistic validation that confirms for us that we, in fact "matter." This is an interesting play on words because matter could mean that which has mass or even the slowed down state of energy, while it also means something of importance or significance. The truth is, we don't always get the love that we put out, back in return.
The point here is that when we give freely and expect nothing in return, when we do get something back it has that much greater importance because we know that it is real, true and comforting - instead of life sustaining. If we do not get anything back, what we we yielded from the experience was that we were able to give because we have the very capacity to carry it out.