We (France) had contracts in Iran. The US decided that Iran is bad.
So far so good.
Then the US said that everyone must leave Iran, and if they do not, their presence in the US will be harmed and they will not be allowed to trade in USD.
We asked the EU for help. The EU said that this is really [bad|unfriendly|unethical|immoral|whatever] of the US to behave that way and that we are, collectively, definitely offended. But that they cannot help.
So we left Iran, together with the rest of EU companies.
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This is just one example of the extraterritoriality that the US does, without any special concerns for international law or relations. One could say "[US|China]are big and strong so they rule", which is true. Not the kind of relationship I would like to have on a personal level.
We frown at bullies in everyday life, but accept this on a national scale.