From my experience I would say slavic people and slavic/catholics.
Well the baltic coast feels near the other coast countries and Scandinavia I think...
Don't listen to fascho's bs. He was 45 years behind bars. ;)
Bavarians to ITALY
Northwestern region close to SCANDINAVIA. Dutch is because of historical reasons for them not an option.
Western Germany to France and Belgium and Luxemburg.
Saarland was a historical argue spot. They are since a longer time German again, but who knows...
East Germany has 45 years of communism so maybe the closeness for them to others is based on that. For the northeastern part I would say Baltics and Scandinavia.