BasketCase
Username sez it all
Well, that's certainly a lot more readable than some of your previous posts. If you said this before, I missed it.To make it clear: my point is that the biggest problem with a communism is the need for perfect cooperation, which is purely unattainable.

We agree, then, that communism is impossible? Fine by me.
Okay, this must be where we get our wires crossed. Most of the stuff I've written previous is reasons why that required cooperation among the citizens is unattainable.So, if you didn't list that as the number one reason for why communism will not work, then I assume that you assumed it was the case, and are pointing to the problems supposing that unattainable goal has, in fact, been attained.
How about invasion by another society?And, under this perfect construct, it seems highly unreasonable to think that there will be any other real problems, such as corruption of power, or general disagreement amongst the populace, given the perfectly cooperative society already formed.
Or, here's another one. Suppose all of us here in CFC decided to form our own communist society this very minute: the Communist Federation of Citizens....

Problem is, all of us are computer nerds. Let's assume that the population of CFC consists of 472 software engineers, 155 web developers, 50 scientists of various persuasions, and 23 lawyers. Here's the problem: there are no doctors or automobile mechanics or farmers or plumbers or electricians in the bunch (just assume this for the sake of the exercise).
Somebody in this crew is going to have to change professions; we need doctors and automobile mechanics and farmers and plumbers and electricians--most particularly farmers. And all of us hate doing these things; we're computer nerds. So, in order to get people to change to the professions needed for the Communist Federation of Citizens to survive, one of two things must be done: either people must be forced to retrain, or they must be tempted with a larger paycheck. Yeah, I know--somebody's going to claim that some of the people will be convinced to change professions for the good of society. That's not communism--it's the central tenet of fascism. And it also produces a disadvantaged lower class: the class of people who were pressured by the masses to change professions.
So either people are forced to do stuff against their will, or different groups of people start earning different paychecks. One way or the other, a class structure will emerge, whether by force of law or by economics.
Those are just a couple. Use your imagination, and other problems will pop up--even among a population of perfectly willing and cooperative citizens.