OSM data is big. Processing, or importing the whole planet file (or europe) can take a while, and it sucks if your data processing job is misconfigured and dies after a few days. It's good to try with a small area first.
@amapanda ... To clarify: character encoding. UTF etc. Farœr is good for that too, btw.
But all those are islands. And I prefer a dataset with cross border artifacts. Because those often go wrong. Islands commonly don't have roads, rivers, lakes, pastures etc that end outside the dataset. At most a ferry line or the sea.
@amapanda OSM tutorials often suggest Iceland. I use it to smoke test encoding issues🙈