. . . is how easily they give up on their national identity to identify as Russians. Here is one example. Blizzard has announed a championship between its professional Starcraft players. Two of the top competitors are Ukrainian (which everybody who follows the championship knows because they are kind of famous). But in the list of competitors you can see here they are identified as being from Russia. (See the comment section for the discussion of where they are really from).
Centuries of colonial domination first in the Russian Empire and then in the Soviet Union (as well as the attendant brainwashing) have taught Ukrainians to be ashamed of not being Russian. We were constantly made to understand that being from Ukraine somehow made us uncultured, uncivilized, and stupid. Even today, 19 years after Ukraine finally achieved its independence, Russian media are filled with nasty jokes about the stupidity and greed of Ukrainians. So when Ukrainians have a chance to make a good name for their country internationally, they often forego this opportunity in favor of presenting themselves as Russian, which somehow makes them feel better about themselves. This is too sad for words.