The EU can often be an unpopular cause on a ballot paper.
In 1997 and 2001 Switzerland voted against its government’s wishes to join the EU.
In 1972 Norway voted against its government’s advice to join.
In 1973 Greenland voted to leave the EU, and eventually did leave.
Denmark voted down the Maastricht Treaty favoured by its government. This led to major opt outs from the Treaty including from the Euro before the Danes would consent.
In 2001 Ireland voted against the Nice Treaty. The EU had to grant opt outs from the military union and other matters.
In 2000 Denmark voted against joining the Euro, confirming its earlier vote against Maastricht. Its government still hadn’t got the message.
In 2000 Sweden voted down joining the Euro, and to this day violates the Treaty by not joining.
In 2005 France and the Netherlands voted down the European Constitution. This was rebranded as Lisbon, despite the popular dissent.
In 2008 Ireland voted against Lisbon, but was persuaded to change the view following some changes to their text.
In 2015 Greece voted against the Euro austerity policies, but subsequently gave in
In 2016 The Netherlands, against its government wishes, voted against the EU/Ukraine Agreement, which the EU has ignored.
None of the dire economic predictions made at the time of some of these votes came true. Norway and Switzerland are the two richest countries in Europe per head, despite not being members or because they are not members. Nor did the rosy forecasts of the pro EU sides come true where they prevailed. Greece who did as she was told by the EU lives to this day with a deeply damaging long recession.