Humans are flawed, greedy and will on the whole work towards their own interests. It's why communism never works beyond the scale of small communities of like-minded people IMO.I think communism can't be done. I'd go that far - I think it's so unrealistic that it's downright impossible and any attempt to implement it will result in a power vacuum that will be filled by a ruthless authoritarian regime and the result won't really be communism.