In his analysis of the movement of history, Marx predicted the breakdown of capitalism, and the establishment in time of a communist society in which class-based human conflict would be overcome. The means of production would be held in the common ownership and used for the common good. In the mention of "human liberation" one should not neglect that, in the level of production, solely the working class is the most oppressed. But either way in the prediction of the future, one shall first know of the past (i.e. the establishment of capitalism and the transitional part of feudalism).
Well, then the historical record finds Marx to be fantastically wrong. Communist societies, instead of eliminating class-based conflict, ensconced it, and perpetuated it. The upper class being those connected to the powers and levers of government, and the lower class being: everyone else.
What's with the reliance on these very bull-crappy imprecise terms like 'common-good'? This is subjective, and probably very intentionally so, since the only definition that matters is the one wielded by those in power.