Growing up as an American citizen, I was taught that a communist government does not work for many reasons. For example, citizens are all supposed to be equals. This may sound good at first but people do not have an opportunity to improve. This then causes a lose in interest and a decrease in effort.
Example: Two neighbors have the same job with the same pay rate. One of these neighbors, Bob, always tries his best and works hard. The other neighbor, Sam, is very lazy and likes to slack off. If Bob does more than Sam does, then Bob deserves more than Sam does. But in a communist system, Bob and Sam would still be treated as equals and neither would be rewarded a raise. Bob then realizes that he can still slack off and get paid just as much, so he stops trying and the quality of his work decreases immensely. If the work isn't done well, then it is done incorrectly, and no one wants that.