I think that communism would work if humans could learn to be that way. But the thing is that humans naturally are the way we are now. People want more for doing more. The idea that everybody contributes to society in some form no matter what they get is great, but humans will never think that way. I dont think what we are doing now is rewarding the greedy, but we are just using a system that works the most with the type of society we have now. It's better to have a system that works for the society we have now then to use one that forces humans to think in a way that is not natural. I also do not think that wanting to have more is greedy, it is also just a natural thing. Again, I am not against communism, in fact, I think it is a great idea, but i understand it could never work.