The US is not exactly one country. It's more like 50 waring states bolted together by a fairly thin federal system. Europeans would be surprised at how much the fed doesn't actually control and what is done is controlled by proxy.
Regardless. The first past the post system in both the US and UK create a "loudest mouth wins" system, which makes it appear like the countries are rabidly crazy. But they're actually just subjugated non-democracies.