Firstly, EU is lending money which Poland has to pay back with interest,
That's point blank wrong. The EU doesn't lend money , it's grants it. It's a gift.
better than being in a slum estate in Bradford.
Having done that, I agree. Happiness is not wealth is it.
spending them in a sensible way is another
Infrastructure aside, the EU is supporting even small businesses with grants. For exampleMy sister in law is waiting for a 100k pln from the EU to expand her markets. It's a long complex process (for good reason).
Other grants are for a cesspit and solar power installations.