There's a ton of related frictions too, FATCA makes it impossible for US persons (including citizens) to open a bank account in a many foreign countries, especially European ones. SEC regulations preclude Americans from opening foreign brokerage accounts. Any aggregate bank account balances over $10,000USD at any time in the calendar year requires filing with FinCEN - [edit] and failure to do so may result in forfeiture of up to 50% of the balance of said accounts.

Starting a business while abroad is especially painful as you are the beneficial owner of a controlled foreign corporation, and the tax reporting there is its own special hellscape.