It's the perfect example. No one won in this situation because both sides got what they wanted, McDonald's got $10 and you've got a burger, if you weren't prepared to pay $10 for a burger you wouldn't have engaged in the transaction. It's exactly the same with international trade, the United States gives some other nation two billion dollars and in exchange they get a cargo containers worth of iron or whatever, if the United States was not prepared to pay 2 billion dollars for the iron, they wouldn't have done so.

In boat scenarios no one is forced to do anything they don't want to do and no one is getting taken advantage of.