Communism does not work because

1.) The power that needs to be held by someone in order to force people to contribute to a socialist economy without direct benefits to themselves corrupts the people who have that power, which they then use for their own benefit.

2.) There is no motivation to work hard and contribute what is your "fair share" if you know you're going to get the same amount in return no matter what.

3.) Trying to plan a national economy is too complex for people to understand, and therefore mistakes are made, which result in either overproduction or a shortage, which often involves poverty or starvation.

4.) There is no freedom for people who do not want to live in this society, and those who hold power must oppress these people to ensure that they continue to hold power, leading to popular unrest among the people, no matter how controlled they are.

This being said, try to find a Communist country that has not experienced the flaws.

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"It is extremely difficult for our contemporaries to conceive of the conditions of free banking because they take government interference with banking for granted and as necessary"

-- Ludwig von Mises