In my opinion overtaking should be part of the driving test. I'm sure people thinking its illegal and/or dangerous. (its only dangerous if done dangerously)
Or even how to allow others the space to overtake even if you don't wish to.
I tow a caravan, so am limited to 50mph on single carriageways. I've often got a long line of traffic behind me. No doubt I'm been cursed for causing the queue, but more often than not, it's the one or two cars directly behind me that are causing the problems. They are far too close to be able to see clear road ahead to be able to overtake if they want to. If they don't intend to overtake, then they are lengthening the line of traffic for those further back in the line who can see clear road to get past.
If I'm towing and am following a slower vehicle, there's probably not many opportunities for me to be able to overtake, so I'll always hang back, giving those behind the room to pull in front of me if they overtake me.
It's not difficult to comprehend, but so many people have little understanding of considerate driving or spacial awareness. We just need to appreciate that and not get worked up when they do something stupid.