This is mostly related to WWI. Because in WWI, Germany was the defeated country. And the west of Britain, France is a victorious country, the east in addition to the restoration of Poland, replaced the Soviet Union of Tsarist Russia, the other almost all of the former Austro-Hungarian Empire after the dissolution of a number of small countries (such as Hungary, Austria, Czechoslovakia, Yugoslavia, etc.), they (both east and west of the neighboring countries) are almost all hostile relations with Germany. As the initiator of World War II, Germany had to "fight one against many" in order to expand abroad, which was an inescapable reality!