Raymond Sontag identifies a possible reason why European governments were taken by surprise by Ukraine’s about-face on the agreement with the EU:

The problem is that many in the West see “balance of power” and “spheres of influence” as antiquated and less-than-legitimate concepts and therefore largely ignore them. Rather than viewing international politics as driven by competing interests, they see it as driven by the process of ever more countries adopting Western-style democracy. Accordingly Western leaders assume that East European states integrating with the West is a natural process in the post-Cold War world and that anything running counter to this integration is a perversion of that process. This disregard for traditional power politics and the assumption that European integration is a natural development are significant blind spots for Western leaders. And these blind spots hamper their ability to realize the very worthy goals of European integration and democratization.

This may apply in some cases, but my impression is that American and European advocates for the eastward expansion of Western institutions and alliances are only too happy to see everything in eastern Europe and the former Soviet Union in terms of balance of power and spheres of influence. Many Westerners may ridicule the concepts by name, but they think in these terms just as much as anyone else. If that were not the case, there would not have been so many overwrought Western reactions to Ukraine’s decision.

If Ukraine turns down a deal with the EU that wouldn’t have given it very much in the near term, many Westerners treat this as an extremely meaningful event rather than the perpetuation of the status quo that it actually is. As Western institutions seek to expand their sphere of influence, Westerners are annoyed that there is any resistance to this, and they complain about Russian efforts to retain influence with lectures about the obsolescence of spheres of influence. However, the complaint isn’t so much that the Russian response is outdated as it is that it is at least temporarily successful. The real trouble is that many Westerners ignore the interests of the nations involved in the expansion process, and instead simply assume that their interests must align with those of Western institutions. When that proves not to be the case, they are left with little to do but splutter in frustration.