Probably the most clear-cut dissimilarity between Germany when it was divided and the present state of affairs on the Korean Peninsula is the status of cross-border people-to-people contacts and relations. In the long years of Germany's division, a multitude of communication channels existed between the two parts of the country.
The division of the Germans was at no time so drastic as it has been and continues to be in this part of the world. There are many reasons for the rigorousness of the Korean divide and the almost complete barring of any human contact. The most crucial factor may be found in the legacy of the Korean War (essentially a bloody civil war), which has left deep scars in the collective conscience of the Korean nation.
Over the years, governments on both sides cultivated a climate of hatred and enmity, creating hostility in the minds of the people. These stereotypes need to be overcome for national harmony to be restored. And national harmony -- this goes without saying -- is an essential precondition for successful reunification.