1. Reunification promised to quickly alleviate forty years of East German Socialism by means of tax money: Prior to and especially during the November 1990 reunification election, political parties and government leaders all agreed that East Germany could be raised to the West German standard of living within the time of one parliament (four years), largely by means of State funding, although much of the GDR remains in the same condition that Hitler left it in.
Reunification advocates ignored the post-War lesson that the western parts of Germany were not rebuilt by means of tax-money but by hard work in a relatively free economy. The people of the Federal Republic of Germany had to work hard for years and years to rebuild their economy. However, most of the people of the former GDR still cling to the old socialist dream that poverty can only be overcome by the State, and the German government is extremely weak in arguing against this mentality. For the most part, the German government instead sends billions of Deutschmarks to the former GDR and promises wealth without hard work, since hard work is so unpopular. This attitude is reflected in a common jest concerning a former GDR citizen who, after reunification, starts to work at the Mercedes assembly line but at 10:00 am complains to his co-worker: "I am tired. We are already over the time, and the material usually runs out."
2. Reunification promised to bring "social freedom" by ignoring the crimes of former Socialist party leaders: In the "Entnazifizierung" following World War II, thousands of Nazi criminals were brought to American and, later, German law courts. Not all Nazi criminals were found or sentenced, but justice became a part of the common mentality, and former Nazis remained silently powerless for fear that common citizens could take them before the courts.
In contrast, the German government has not attempted to restore this sort of criminal justice in the former GDR. Thousands of the leading members of the SED (the East German Socialist party) are criminals even by old GDR standards, but, as of yet, German citizens are not bringing lawsuits against such criminals like they did following World War II. Most former GDR citizens fear to talk about known crimes, because SED leaders still control most of the factories, city administrations, universities, and even courts of law so that SED leaders are still able to work against "capitalistic" citizens. Freedom cannot prosper without justice.
3. Reunification advocates condemn the statism of the former GDR but ignore the statism of the FRG: The German government holds numerous state monopolies, some of them official (post, telephone, railway, local transportation, public education), some of them by way of ownership (airlines, electricity), and some by strict regulation (long-distance transportation -- businesses need a government permit to transport goods further than fifty kilometers). Moreover, Germany has an extensive social welfare system in which citizens must contribute to state insurance for health, unemployment, and rent.
Thus, former West German politicians have a difficult time explaining the difference between statist socialism and statist "capitalism". Of course, they refer to it as a "social market economy," but this is simply a euphemism for the old promise that the State will subsidize citizens that are poor, ill, unemployed, old, or just not willing to work. The former GDR promised this to its citizens, and this is what they still expect.
The new government promised this to its citizens in order to win the election, but this promise and the others noted above will hinder a second "Wirtschaftswunder".