Anybody just hopped in the car and driven to Europe?

Just be aware that there is this one bizarre rule where a person joining a road from the right has the right of way.  If I ever have an accident, it will my be because of that.

Is this joining a motorway or just any junction in general, eg. a crossroad

Best to look it up, but I think it's not about merging in to a motorway.  It's about junctions. 
Even if you are just cruising along, the road joining on the right has priority.  Unless
If it's a main road and a smaller road, the smaller road on the right will  sometimes have a sign saying that they no longer have the right of way.  You'll have a sign as well saying the same thing with inexplicable arrows.

I can be of no help really...except that I think I remember the guy writing about it in A Year in the Merde.