Why is it that when conservatives argue that socialism has been a failure, they always point to the USSR?

We DO point to countries like Denmark and Sweden, where the average person has two or three jobs because they CANNOT meet their needs with what their government let's them keep from their ONE "official" job; where the people think their medical "system" is great even though they are dissatisfied with their OWN experiences and where 4/5th of their population have less living space and fewer "luxuries" than do the American "poor."