I don't exactly know what crosses the mind of those consumed with greed. I just assume that it is an overwhelming and strong sensation/feeling. People who allready have what they need in life but continue to crave more and more, where does such sellfishness stem from? It's like an undying and everlasting thirst for more. But more of what exactly? People like this can have all the riches in the world but still seek out to retrieve possesions to compinsate for whatever it is they may be lacking. Is it peer pressure? Is it a void that they are trying to fill? Is it a compulsive behavior?
But as well as greed lies in a materialistic aspect , it also pertains to relationships. Now how to you respond to someone who feels like they can have their cake and eat it to? Its easy to just say "F*** that person ,move on!" But when emotion and feelings are involved its easier said than done. Its just a matter of focusing on the issue at hand, you are being taken advantage of. Now use that as motive to muster up the courage and strength to look that person in the eye and walk away. But you walk away with your head held high, not with your tail between your legs because although you left them showing them they hurt you gives them that power, your giving them your power. That power is yours and only yours. Don't let someone else steal your joy , don't let anyone steal your glory. Keep God the center of your focus, keep your eye on the prize. Greed leads to sin, greed cause pain inflicted on others and on yourself. Don't fall into greed. Allow your greatness to overshadow the greed.