system
Given the following post, respond as if you're commenting on Reddit:
human
Is the main barrier to communism greed?

If you accept that the principal of communism, everyone being equal, is good; is the only reason communism doesn't work that at some point someone will want more for themselves?

Edit: thanks for your responses they're all very interesting and helpful, im not sure how to mark the thread as answered but I realise that a communist community would struggle to move forward due to lack of reward. My follow up question to this would be is there a reason we require reward in order to do things? Would a communist community work if it were ingrained from a young age that you should do things just because you want to/are needed to or is it in human nature/animal nature to need a more tangible reward? But I suppose they're probably more philosophical questions that would merit another thread.

Edit: Sorry this is more of a discussion now, the original question was answered, or at least I am satisfied with the thoughts it provoked. Thank you for your time :)
gpt
Sort of. 

I'd argue that the main barrier is a removal of what makes people strive for betterment. Why would a craftsman make beautiful tables if he gets the same pay for making crappy tables? Why would anyone invent anything? Why would a janitor clean faster if his pay isn't based on performance? It's not really greed, it's human psychology. It isn't just about money; its about being rewarded. And, this is exactly what we saw in places like the Soviet Union. People just working mindlessly, not trying to improve their methods or be innovative.