I don't really have favorite examples, but you can find them everywhere, as the dichotomy ties together the things that we focus on all the time as commies. The base is (for us) capitalist social relations to production, a dominant force, and the superstructure is the other social relations we have. As a dialectic, they influence one another, both in favor of capital on average, with the base largely determining what is possible and how people can imagine a world in the superstructure and the superstructure, in turn, helping ensure the maintenance of capitalist relations to production.

The recent (almost) rail strike has examples of both and we can all see who won there, and it's a story that plays out all the time: relations to production create the contradictions leading to an impetus for unionization and striking but also forwarding the interests of the owner class (dominant) means that the government (part of the superstructure) will intervene on capital's behalf to crush labor rather than crush capital. The idea that the government would nationalize BNSF or force it into collective ownership is unfathomable in the imperial core. And by crushing worker power via the government, capital is reinforced.

There are other salient aspects of the superstructure here as well. The mainstream media holds vast sway as the only source of information most people seek out, and it unilaterally accepts and forwards the pro-capital narrative that it's rail workers vs. the economy rather than greedy capitalists (or, better, owner class interests) vs. the economy. To try to understand how that can happen, how the obvious and true narrative is entirely absent, we have to understand the influence of the base on the superstructure: why every mainstream editor follows a pro-capitalist strategy when hiring, when editing, and who's on editorial boards. And even before that, why an anti-capitalist analysis is never taught in school and instead one learns fairy tales about meritocracy and material well-being. Why unions don't have the ear of the press. Why the left gets shut out of social media platforms when they get too explicit and too many people start listening. Why we can't mass-mobilize to support striking workers even when we want to (work or die). And because all of those things are constrained in favor of capital, capitalist social relations are reinforced: the union is weaker, the rail companies stronger, working to eat becomes more extreme.