Just take two seconds after you get routing directions up to zoom out and verify it's going about where you want to go.
I've driven in Iceland before and it's impossible to not go to Reykjavik if you pay even the least attention to signs, or just look at the map where you can see where Reykjavik is in relation to where you are driving.
I really like using Waze to guide me, not even by giving directions (which I often ignore) but just to see what roads are around me while driving so I can quickly adjust pathing to something that makes more sense.
One gripe I have with all modern nav systems is that I really wish I had a lot more control over the routes - like "avoid highway if possible" or "Your traffic predictions are always wrong, do not believe their lies". At least Apple Maps gives you three different routes to choose from, that's a nice start but I'd like to be able to guide it further.