26 Feb 1986, Denmark holds a referendum on creating the single market. 56.2% in favour of creating the market, referendum result upheld.
26 May 1987, Ireland holds a referendum on creating the single market. 69.9% in favour of creating the market, referendum result upheld.
2 Jun 1992, Denmark holds a referendum on the Maastricht Treaty, which would surrender their currency, bank, citizenship, foreign policy and supremacy of law, leading to the creation of the modern institutions of the EU.
Danes vote against it with 50.7% against, made to vote again. At least they got 4 opt outs, for a while.
20 Sep 1992, France holds a referendum on the Maastricht Treaty, 50.1% in favour, referendum result upheld.
18 May 1993, Denmark holds their redone referendum, 56.8% in favour of the treaty, decision upheld.
28 Nov 1994, Norway holds a referendum on accession to the European Union, 52.2% vote against and thus they remain outside of the Union. Ignoring the result, their government signs them up to the European Economic Area without referendum, leading to the funny situation where the Danes and Britons within the EU are less integrated than the Norwegians outside.
22 May 1998, Ireland holds a referendum on the Amsterdam treaty, giving away control of immigration, adopting civil and criminal laws, enacting common foreign and security policy (CFSP), as well as implementing institutional changes for expansion as new member nations join the EU. 61.74% vote in favour, referendum result upheld.
28 May 1998, Denmark holds a referendum on the Amsterdam treaty. 55.1% in favour, referendum result upheld, losing their citizenship opt out and migration opt out.
28 Sep 2000, Denmark holds a referendum on whether to lose their economic opt-out. The Danish Economic Council correctly gauges that the Euro is a political project, not an economic one, and the EU sanctioning of Austria shows the Danes how the EU was beginning to control the affairs of its smaller states. 53.2% vote against, referendum result upheld.
2001, the Irish hold a referendum on whether or not to pass the Treaty of Nice. 53.9% of Irish voters reject the treaty.
They are made to vote again.
With the second referendum taking place in 2002 it passes with 62.9%.
Second referendum result upheld.
29 May 2005, France holds a referendum on whether to ratify the European Constitution. 54.9% vote against. The Netherlands holds a referendum on the European Constitution, 61.5% against. The European Constitution is struck down. 4 years later the European Constitution is rebranded the Treaty of Lisbon, the French and Dutch are not given referendums, no one except Ireland is.
12 Jun 2008, Ireland votes on whether to ratify the Lisbon Treaty. 53.2% voted against, made to vote again.
2 Oct 2009, Ireland votes on whether to ratify the Lisbon Treaty. 67.1% voted in favour, referendum result upheld.
5 Jul 2015, Greece votes on whether to accept the Troika's economic conditions. 61% of Greeks vote no - with the majority of every region of Greece voting to reject the Troika's measures. In a way the referendum result was upheld, as the Greeks are made to accept even harsher terms.
Interestingly whilst our Prime Minister John Major signed us up for the Maastricht Treaty without referendum, the majority of the Conservative MPs opposed him and threatened to no-confidence him into retirement. On the 22 July 1993, the Labour Party tries to pass a postponement of the Treaty through Parliament, with support from the Tory bloc the bill gets stalemated at 317 in favour, 317 against - with the speaker casting the final deciding vote. The government is nearly brought down 3 times. In response for failing to support their leader in their leader's support of the EU, changes to Tory party membership were made to allow new MP candidates to only be selected as approved by the whip or from a list of candidates. Furthermore, party leadership could deselect a rebellious MP's candidacy, remove their whip or have their association suspended if they disobey the Conservative Central Office. We got a lot of good opt-outs from their sacrifices.
Remember, if you don't like the result, make them vote again - that's democratic xD