Like matter and antimatter, light and darkness, heaven and hell, the Moscow underground is antithetical to the Western world's undergrounds that happen to be fair pictures of the underworld.
Neither litter, damage nor graffiti in the Moscow metro ever offends the natural need for harmony and aesthetics of every well-born and mentally well-formed person.
No feeling of insecurity or no real threat will disturb the peace of mind of the traveler. The underground is a reflection of the surface, a continuity of ground floor life where order, safety, courtesy, craving for culture and beauty rule.
Continuity is a watchword that defines on one hand what a traveler can feel in the Moscow metro, and on the other hand what is appallingly lacking in the metros of the Western world. Continuity of people, culture and normal life in Russia, and absence of continuity of all areas in the Western world history that corner more and more individuals or groups into cognitive dissonance.
One cannot but remind these words from Dante's Divine Comedy, when leaving Inferno: E quindi uscimmo a riveder le stelle (“And then we emerged and saw the stars again”), first while emerging from the underground of a city like Paris, then hopefully crossing France's border heading to some land of the free outside the EU. Of course outside.
The costume from the film “The Empresses” (Императрицы) exhibited at Mayakovskaya station, Moscow, would not last in such pristine condition more than a few hours or a day in Paris or London metro even with 24/7 heavily armed guards. And that says it all about the infinite distance between Moscow underground and the true underworld of what happened to become Western European cities nowadays torn between proudness of their past grandeur and dumb blind obedience to self-destructive submission to "old Christian virtues gone mad", to borrow the phrase of G.K. Chesrton.
However, better than Continuity, Heimat will define even deeper the relation Muscovites and tourists have or discover with not only the metro but also the city of Moscow that are constantly improving and expanding the quality of their infrastructures and services.
As a citizen or a traveler, just tell the city you're staying in this question: Show me your underground and I'll tell you who you are!