Greed simply means doing all things primarily in your own interest (either directly or indirectly).
In common usage it usually means doing all things primarily in your own interest,
at the expense of others.
More and more scientific evidence seems to show us that cooperation tends to get one a better life than cut-throat
competition. Some may suggest that is what separates humans (potentially) from wild animals... but even modern
studies seem to show us that there is more cooperation in, wild and red in tooth and claw, nature then we had previously
thought.
This little ancient allegory below I feel illustrates it very well ( despite it appearing on the surface as some sappy sunday school story,
it was originally Taoist, I think, but often gets mangled into some Christian form for use in the modern West ):
There is a story about a man who left this earth and was taken on a tour of the inner realms. He was shown a room where he saw a large group of hungry people trying to eat dinner from a single large pot in the center of the room, but because their spoons were longer than their arms, they were frustrated. "This," his guide told him, "is hell." "That's terrible," the man exclaimed. "Please show me heaven." "Very well," agreed the guide, and off they went. When they opened the door to heaven, the man was perplexed to see what looked like exactly the same scene: there was a group of people with spoons longer than their arms and the same pot of food in the center of the room. But as he looked more closely, he saw happy faces and well-fed bodies, for there was one important difference: the people in heaven had learned to feed each other.
