Why is enough never enough?

This intriguing question goes to the heart of much human dilemma.
The Carclew Youth Arts Centre have been working this question through in various forms (see here)with an impressive array of talent and young thinkers.
It is the sort of question that will inevitably drive such as me insane for the next few months.
Observation 1:I am thinking at the moment that "enough is never enough" is actually a key evolutionary response of the human species that has caused us to advantage ourselves and to find that we are at the top of certain trees (debatable)
If this is so, then when we begin to get it through our thick heads that this grasping will also sow the seeds of our destruction as a species then maybe evolution will occasion a change in attitude too. But evolution takes a long time.
Observation 2: Is blogging also a manifestation of the enough is never enough phenomenon...bloggers do carry on don't you think.
Observation 3: Religion, a much scoffed-at mechanism these days, maybe is one of the few mechanisms that can confront this suicidal principle. Can you get enough religion?