What is the reason for the discrepancies between Western and Eastern Europe?

1. WWII was far far far more of a tragedy for Eastern Europe than Western Europe. Most of the fighting and dying and displacement and literally millions of tragic horrors of that war went on in Eastern Europe. The Western front was little more than a sideshow to the main attraction which was the clash of two terrible totalitarian civilizations — Germany and the Soviet Union. The Holocaust happened here, and lest we forget, the Soviet Union had about an equal if not greater amount of people imprisoned in work camps, most of whom died.
2. The aftermath of the War allowed the Soviet Union to pillage the industrial factories of Eastern Europe — in a climate where starvation and depravity had traumatized the people into accepting atrocity as normal, the stealing of their nation’s wealth by the Liberators just seemed par for the course.
3. Reciprocal atrocities to ethnic Germans living in post-war Eastern Europe put a psychic stain on the countries.
4. The political environment of Communist Europe absolutely depended on ordinary people to carry out the regimes’ dictates. Totalitarianism doesn’t work unless your friends, relatives and neighbors can’t be trusted.
5. While post-war Western Europe had the Marshall Plan and a generally benevolent leader in the USA, who realized that the path to peace was prosperity, Eastern Europe had a mad capricious system that didn’t work and pretty much ate humans alive by the millions in some attempt to remake the world in an ideal image, even though that image was ugly, featureless and uninspiring.

All of these things left psychic scars on the people. IN my opinion, they have less faith in institutions than the West: because for too long the institutions were part of an inhuman, absurd system. AS a result, public areas are a bit less kept up, more dishevelled and ragged-looking. There seems to be less civic pride. (It is actually a poor way to judge a nation’s wealth, though — many Westerners make that mistake.)

When the governments fell, there was a mad rush to make money by Westerners and Easterners alike; this fostered a mafia culture to some extent; the EU has pretty much eradicated those problems in most countries(other than Bulgaria, perhaps) but they are still very much a thing further East(Ukraine and so on).

After the Cold War, the lands of formerly Communist Europe were at a severe disadvantage economically to the West. Western companies were easily able to snatch up factories for a good price, locking the people into a relatively low-wage existence. People in power facilitated that as a way to make the country grow economically.

But it created a catch-22: if the wages go too high, the foreign companies leave and there will be unemployment.

I live in the Czech Republic and my perspective comes from that. Other countries might have slightly different narratives: indeed, the Czech Republic is not that bad off and is becoming more “German” every year; by which I mean, more organized, more business-like, more proud of it’s institutions, better dressed and more “Western European”.