In China, why do conflicts often occur between upstairs and downstairs neighbors?

Many people think it's because the children upstairs don't have good behavior, jumping around randomly, often dragging chairs, dropping things that make noise, and other noise issues. But in reality:
Look at a set of data:
Chinese ordinary commercial residential floors are 10-12 centimeters thick.
Japanese standard reinforced concrete residential floors are commonly 18-25 centimeters thick.
Many European countries' concrete residential floors are typically 18-30 centimeters thick.
The situation in the United States is quite special; many residences are wooden structures and do not necessarily use concrete floors; if it's an apartment or high-rise, concrete floors are often over 15-25 centimeters thick.
Now look at another set of data:
The cost composition of a house in China:
Land 30%-50% (government)
Taxes and fees 10%-20% (government)
Building materials and construction 15%-25% (construction industry)
Development and operation 5%-10% (developers)
Development profit 5%-20% (development)
Shareholder interest financing 5%-20% (banks and capital)
So, can you understand? Who is the problem? Is it the noise between upstairs and downstairs neighbors? Or is it the building standards, the mechanism layer, and the cost distribution, the structural layer?
It causes conflicts to always remain in scarcity and neighborly scarcity.