In the plumbing sector, left-hand threads are used whenever two pipe ends need to be connected that cannot be rotated. The connector is then equipped with a left-hand and right-hand thread and can therefore easily be screwed between them.
So it’s not just typical for Nordic countries, but depends on the application.
Exactly! Bicycle pedals have a left-hand thread on the left-hand side and “normal” threads on the right-hand side.