It's an interesting and thought-provoking subject. I actually think the examples you mention are not so much about greed as about insecurity. Many people feel the need to possess things that they could easily share, or rent - for example, a pair of fancy shoes that they will only wear once. It's because they feel insecure.
I will never understand those ppl that buy shoes only to wear them once... i think i wear mine until they start to deteriorate, i like my money (guess i'm a little greedy with my money)... thanks for reading!