Russians are usually close to Ukrainians who live in the east and in the central part of Ukraine. Ukrainians who live in the western part usually feel closer to the polish. There are also good relations between Russians and Belarussians. Despite the fact that Bulgarians and Serbs are south-slavic nations, there seems to be a strong connection between Russians and Bulgarians and Russians and Serbians (maybe because of the OCS language and the liberation war in 1877). Last summer I've visited Bulgaria and everyone there seemed to like Russians (especially when I talked to them in Bulgarian).