In Spain, which elects the fifth-biggest contingent of lawmakers to the European Parliament, the staunchly pro-EU Socialists won big in the polls, taking close to 33 percent, tailed by the conservatives who also view membership to the bloc favourably.
Compared to other major EU states such as France or Italy where eurosceptics came first, citizens in Spain are broadly pro-EU, said Jose Ignacio Torreblanca of the European Council on Foreign Relations think-tank.
And that is because the EU rhymes with freedom.
READ MORE: Spain's Socialists win big in EU vote
The EU election results from Spain show big win for PSOE. DATA: Interior Ministry
Spain's return to democracy following the death of longtime dictator Francisco Franco in 1975 and its entry in 1986 into the then European Economic Community “are two sides of the same coin,” he added.
Even far-right party Vox, which entered the European Parliament for the first time with three seats, is staunchly pro-European.
It does not want to leave the bloc, the euro or even the Schengen zone that drops some internal border controls.
EU membership helped thrust Spain into the modern world. EU development funds for example helped the country build Europe's largest high-speed rail network.
The same goes for Portugal and Ireland.
“These countries were transformed by their membership of the EU,” says Jean-Dominique Giuliani, president of the Robert Schuman Foundation think tank, which would explain the lack of major eurosceptic forces.
Dublin for instance “became the gateway for investments of the Gafa (tech giants Google, Amazon, Facebook and Apple) in Europe.”
Exit polls showed Ireland's pro-EU Fine Gael — who lead the current government — and Green party set to score big.
According to the latest Eurobarometer survey published by the European Parliament, 83 percent of respondents in Ireland have a positive opinion of EU membership.
Ireland has received 42 billion euros ($47 billion) in EU development aid since it joined the bloc in 1973, according to Irish government figures.
In all, 700,000 jobs have been created and foreign trade increased 90 fold. Ireland, which will bear the economic brunt of Britain's looming exit from the EU, has consistently been backed by its EU partners.
That is also thought to have cemented the Irish public's commitment to the bloc.
Like Spain, in Portugal 69 percent of the population looks upon EU membership favourably, according to the Eurobarometer, despite drastic austerity imposed by Brussels after the financial crisis.
Pro-EU Socialists won the polls.
The country joined the bloc in the same year as its neighbour after decades of dictatorship.
It has “benefitted greatly from the European project” in terms of improved social services, education and transport, says the head of the ruling Socialist Party's poll list, Pedro Marques.
But what of other member states like Hungary and Poland that also benefitted economically from the EU but elected eurosceptics to power?
According to Giuliani, it's all down to history.
“For Spain, Europe is democracy and prosperity. In Hungary or in Poland, Europe is prosperity, security but it's something that runs up against the desire to recover national sovereignty,” 20 years after the end of communism, he says.
It's a different story for the Baltic states.
The EU and NATO allowed Estonia, Latvia and Lithuania, once ruled from Moscow, to reassert their sovereignty.
They became member states in 2004 and for them, the EU means access to the single market and security in the face of their giant, increasingly assertive Russian neighbour.
On Sunday, Lithuanians also voted in presidential elections, electing Gitanas Nauseda, a pro-EU political novice.
In the Netherlands, meanwhile, projections showed voters showing their attachment to the EU with the social democrats coming first.
Dutch far-right leader Geert Wilders looked set to be kicked out of the European Parliament altogether while anti-EU leader Thierry Baudet was expected to win three seats, far less than expected in opinion polls.
And in Denmark, the People's Party, which had won European elections in 2014 with 26.6 percent of the vote, took a tumble with under 11 percent.