As someone who moved countries within the EU, I started looking at things from global perspective, and what matters today is the power balance between EU, US, China. Whereas within EU most countries still look at their own interest, fueled by politicians and their 4-5 years election periods. This is really sad, because the EU is digging their own grave.

Re: your comment, it's not only on nation level. People have tendency to form groups and build their identity on "us vs them" basis. That's why you have rivalries between football clubs from different cities etc.

Anyway, language and culture/history is a powerful thing that people can't get over in us-vs-them thinking. There's also business in play which collides with politics a lot. For example Germany are fine doing business with Russia, while for Poland, Lithuania and other Russia-bordering countries, RU is #1 evil and existential threat.