Psychology and social/political constructs are dialectically related: our social constructs affect our psychology, and our psychology affects our social constructs: they feed back into each other. We can neither set up an "ideal" set of social constructs, nor can we implement an "ideal" psychology, and hope the other falls into place.
The final stage of communism — true anarcho-communism — will come when the vast majority of people no longer have any desire to exploit others, even when they have the opportunity to do so; the only need for force will be against those individuals with true mentally illness.
This dialectical relationship is important at every level of the transformation of capitalism to anarcho-communism.
We can most easily directly affect social/political constructs; there are severe practical and ethical problems trying to modify people's psychology directly. But understanding the dialectic between social constructs and psychology gives us guidance as to the specific kinds of changes we can make, and lets us distinguish between economism and true reform.
For example, I think it's a good thing to organize labor unions: A union is a social construct that allows workers to act collectively for their mutual benefit; this activity directly reinforces the psychology of mutualism. But employing labor unions to merely ask for a fraction of the workers' surplus value, or allowing senior workers to take newer workers' surplus value does not reinforce the psychology of mutualism, and is therefore economism. The best employment of labor unions is to expropriate the bourgeois ownership of industry, because bourgeois ownership is an exploitative social construct and directly reinforces the psychology of exploitation.
Understanding this dialectic is not an argument for gradualism; it's not an argument to try to ameliorate the conditions of the proletariat under the dictatorship of the bourgeoisie. We need fundamental, revolutionary changes to our social and political constructs just to get this social/psychological dialectic on the right track. Economic relations are also in a dialectic with psychology and social constructs: so long as our economic relations are inherently exploitative, trying to push social constructs and psychology to mutualism will not be effective. (Note too that the inherently exploitative nature of capitalist economic relations degenerate into naked oppression and de facto slavery, creating the conditions necessary for revolution.)
But contrawise it's important to understand that there will be considerable remnants of exploitative capitalist psychology even after revolutionary changes, and the social and political constructs formed after a revolution must account for those remnants and change them as gracefully as possible. Brute force is a poor implement for psychological change.
In the early stages, the transformation of capitalism into early-stage socialism, we will have to take into account the psychological remnants of capitalism — the loathing of "free riders", the contradiction between mental and manual labor, the privilege of the intelligentsia — "respecting" those remnants while seeking to use social constructs to gradually transform them.
The later stages, the transformation of late-stage socialism to early-stage communism, will therefore still require a fairly large government even without class conflict — or, more precisely, the officials of the government themselves will be an economic class, requiring some sort of continuing class struggle between the government and the people. With all good luck, the early-stage communist class struggle can be engaged without violence, since the psychology of those in the government should have been affected by the social constructs of socialism. The "struggle" might well be to create large-scale economic endeavors without using mutualism-coercive state planning.
The dialectic between the social and the psychological changes its fundamental character under socialism, even in the earliest stages.
All class struggles before socialism are fundamentally the ruling class exploiting the ruled class, and the ruled class resisting exploitation. The social and political constructs under pre-socialist class struggles, therefore, reflect and support both the dominance of the ruling class (the ruling class deserves to rule) and also, to some extent the resistance of the ruled class.
The class struggle under socialism and communism, however, is only temporarily a struggle between the ruling class (the proletariat) and the ruled class (the bourgeoisie). This first struggle aims to eliminate the bourgeoisie as a class*, by making it so that no individual appropriates the surplus value of labor by virtue of ownership of capital. The elimination of the bourgeoisie as a class marks the transformation of socialism into early-stage communism, and ends the exploiting-by-ruling economic class struggle.
*Not, of course, by killing bourgeois individuals, but by transforming bourgeois individuals into people who work, into the proletariat. Note that its logically impossible for the bourgeoisie to eliminate the proletariat by making them all bourgeoisie; who would do the work?
Under early-stage communism there's still a managing class and a managed class. There are still classes, but the classes are no longer in a necessarily exploitative relationship. Since there are classes there must be class struggle, but the class struggle is for both classes to eliminate the remnants of exploitative psychological and social relations in the other. The managing class transforms the sheep-like, passive, authoritarian-submissive psychological elements in the managed class, and the managed class transforms the managing class to remove the remnants of exploitative social constructions and prevents the managing class from backsliding into an exploitative position. But more importantly, both classes are struggling to eliminate the need for coercive management.
In the final stages of communism, people engage in mutually beneficial relations not because they bind themselves coercively to prevent exploitation, but because it is the social and psychological norm to abhor exploitation and prefer mutuality. At that point, large-scale macroeconomic planning can be performed not by a coercive government, but by specialized experts who are listened to because it makes rational sense to do so, and those listening have been educated and trained to understand their arguments and explanations.