You cannot lecture on really pure poetry any more than you can talk about the ingredients of pure water-it is adulterated, methylated, sanded poetry that makes the best lectures.
When we cast our bread upon the waters we can presume that someone downstream whose face we will never know will benefit from our action, as we who are downstream from another will profit from the grantor's gift.
But love is much like a dam; if you allow a tiny crack to form through which only a trickle of water can pass, that trickle will quickly bring down the whole structure and soon no one will be able to control the force of the current.
What is significant in one's own existence one is hardly aware, and it certainly should not bother the other fellow. What does a fish know about the water in which he swims all his life?