Overtaking from the right is strictly forbidden.

As it should be. But what happens when you've got some idiot driving 5(units)ph slower than the limit in the left lane and you're actually overtaking him in the right lane? I've spent hours commuting observing and thinking about this problem. Your rule would seem to indicate that you should pull into the left lane behind him, slowing down to do so, and start flashing your lights and honking until he pulls his head out of his ass and moves to the right. In a perfect world, this wouldn't need to happen, but I, for one, don't live in a perfect world. I live in one that contains a load of idiots with their heads up their asses.

I used to do what I just described, as it is really the logically best thing to do, as it will occasionally happen that someone is passing and just goes absent-minded for a second and forget to move back to the right lane when he's done. But in 99% of the cases where I've done that, the idiot just gets mad, not realizing that he's the one causing a disturbance or that making me pass him on the right is dangerous.

This all probably has to do with the remarkably lax requirements for getting a driver's license here in the US. My written test had more questions about what would happen if I used a fake license to buy alcohol than about driving. Oh, well. Enough rant.