Open borders to western Europe, no passwords or visas necessary; easy traveling, possibility to move to any member country and find a job everywhere in a membership country (free transfer of persons) - although not all countries would permit East European to work immediately. In some countries, especially where unemployment is high, Poles need to wait seven years before they would be able to apply for a job.
EU aid - East European countries are promised that they will not become net payers of EU. That means that Poland will receive more money from EU that it will give to EU. Poland should get $16.2 billion in EU aid through 2006, more than half of it for its 2 million farmers. But there are string attached to it. Some money are only potentially available after fulfilling many beaurocratic requirements.
Tightening of the cultural bonds with the rest of Europe. Polish students could participate in the educational programs which give stipends for studying abroad. Children of people who would be working abroad would be able to attend local schools.
Promise of long-term prosperity. Recent poll found 56 percent of Poles believe EU membership will lift next generation's living standard. 43 percent believe that unemployment, almost 20 percent, will gradually decrease. Less corruption in the administration. Lower customs on some imports, such as computers and alcohol. Equaling to higher standards of political, social, economical life in Western Europe.
Short-term job losses. Layoffs in heavy industry and subsidized sectors are inevitable. Over-flooding of Polish market with cheap subsidized Western European food products.
Small Farms can disappear - Over 20% of Poles still works the land. Many farms are small and inefficient, and likely to disappear or be merged into larger holdings in long run. The subsidies can help only big and efficient farms to survive. Read more about it in the article about EU Disadvantages: Polish Agriculture (Farming) and European Union.
World War II claims - Legal disputes with Germans claiming land lost at end of World War II could worsen, because Poland now subject to EU tribunals. Read more about danger of German claims and sellout of Polish land to foreigners.
Modernization and ecology costs - Meeting EU environmental and food safety standards will cost billions. Upgrading social safety net likely to strain economy. Some food prices expected to rise. Some experts state that imposing very high, rigid and detailed Western European ecological standards will ruin Eastern European economy and will cause bureaucracy to grow.
EU creates a huge bureaucracy because it introduces hundreds of thousands of detailed laws about any aspect of economy and political life. It also imposes the rights and laws created in liberal and mostly laic Western European countries onto Eastern Europe which is more religious and has a different cultural tradition. Read more about it here: EU as a supercountry? It promotes liberalism and it can also lead to division into countries of the first and second categories especially now when European economy is in crisis and the subsidies for new countries-members much lower than needed to boost their development to Western European level.
No more delicious goulash (Hungarian national dish) and bigos (Polish dish called also hunter stew) made from cabbage (sauerkraut), meat and sausage (Polish kielbasa). Since these foods need to be re-heated in order to have a right taste which is in disagreement with the EU standards did not agree to serve them in restaurants in any EU member country.
The European Union: A Very Short Introduction by John Pinder
Understanding the European Union: A Concise Introduction, Second Edition by John McCormick