Generally speaking, when talking with a relatively reasonable and intelligent leftists about politics, economics (which are the same thing to them), econometrics, and social philosophy (again, they can't be separated in leftist theology); the "question" will arise "If socialism is so bad, why does it work in families, and villages? It works there, so it should work everywhere."
That isn't so much a question, as argumentum inquisitum (aka "begs the question"), but let's take up the challenge anyway; as the answer is simple, fundamental, and absolutely vital to understanding microeconomics, and how it interacts with societal level macroeconomics.
Collectivism (of any variety) does not work on scales larger than a village, because people will ALWAYS respond to their perceived interests and incentives.
Let me repeat that one more time:
People will always, over time and absent interference, respond to their perceived interest and incentive.
People may (in fact, very frequently do) mispercieve their interest, or may choose a poor course of action in their properly (or improperly) perceived interests, but they will ALWAYS respond to them.
In a family, the incentive and interest are VERY strong, genetically, socially, societally, emotionally, and spiritually; to ensure the prosperity and well being of the family unit equal to or ahead of ones self.
We can see what happens to families where this is not so among the majority of members; or is not so among the "strongest" members (the "leaders" of the family). These families rapidly degenerate into an unhealthy mess of force, fraud, manipulation, pain, and dysfunction.
This is also what happens in society as a whole when collectivist ideology is enforced on it.
One should note, there is no such thing as a naturally occurring voluntary collectivist order above the small tribal group. At larger scales, collectivism must always be enforced on the whole, because it is against the interest of many individuals; until such time as a dependent class is formed which will create an artificial interest, causing that class to act in that interest to enforce collectivism on the independent individuals.
As I said, people will ALWAYS act in their perceived interest. Even in collectivism; which is supposedly communitarian in nature.
In society as a whole, and specifically in societies larger than familial, clan, village, or small tribal level; self interest is a considerably stronger incentive and interest than the interest of society.
Communitarian ideals can generally work scaled up to village size, or even small tribes; but the bigger the unit gets, in general, the weaker the cohesion; unless there is another binding force (such as tribalism, or at least ethnic solidarity).
Also, the free rider problem, which may be one or two individuals within a family, becomes a serious drag on resources even at the village size. It becomes insupportable above the scale of a large tribe or small state.
These village size units work best when the village is itself a competing interest against other villages, or groups of villages united by a common characteristic which creates a cohesive identity.
We call this tribalism; and it allows for progress to a certain point, but is also a natural restraint on it; in that tribalism encourages the violent breakdown of civil culture in conflict with other tribes.
In fact, almost all of the greatest evils perpetrated within the confines of society (as opposed to evils outside of a society such as serial killers, etc...) are the result of violent tribal conflict; including the wars in the middle east and Africa (all of them).
All forms of collectivism fail to recognize or account for the inherent competitive, and striving nature of man; and generally fail to account for his inherent xenophobia as well (yes, certain individuals or small groups may suppress those characteristics, but man as a whole is man; unchanging and vicious from prehistory to this minute. We just have better tools to kill each other with, faster, and on a larger scale now).
Thus, aside from its structural deficiencies, inefficiency, and moral evil; socialism is antithetical to the natural social nature and structure of man (contrary to the assertions of socialists that it is in fact derived from the nature of man, or is scientifically and historically inevitable. Both logic and history show this construction to be elegant, but falacious).