Hmm, thats strange. I spent a whole summer in Moscow and didn't see or hear of any green vodka. But I can shed some light into why Russians can drink so much. Russian families tend to cook at home for special occasions and many people come. Traditionally these so called "dinners" take multiple hours, unlike the traditions in the USA. At the beginning of the meal shots are poured, and the first toast is usually the most important one. Then people continue toasting to what ever they want of the course of a few hours. A lot of alcohol is consumed that way and the kids at the table see this and continue the tradition them selves later on in life. At the ages of about 13 - 18, the kids do kind of the same thing except as underage people they must do it out side at different camp grounds. As age approaches the legal drinking age, the place of partying shifts from outside, to bars. Then with more age and families the big dinner parties occur. Its a cycle. But it is true, refusing a drink is considered bad. You drink until you are ruined and the people pouring drinks stop pouring you anything, or the person of opposite gender that you came with cuts you off. Luckily, Russian food is very hearty and in my personal opinion it helps.