Middle Lane Drivers

Before I start ranting on about the forthcoming topic, I would just like to point out that I am, in no uncertain terms the greatest driver. I have my good points and my bad points. The bad points mainly outwaying the good ones I'm afraid. My recent motorbike theory test highlighted the fact that my attitude towards the road needs to be somewhat more positive.
However, middle lane drivers, and by that I mean cars that stay in the middle lane of a motorway or A road, or the outside lane of a dual carrige way no matter the fact that there is no traffic in the inside lane is a constant niggle of most motorists and really gets on my nipples.
Do these people not know that they should stay in the inside lane? Do they not know that they are causing a high percentage of traffic delays with huge trails of cars that often line up behind them? Do they not know that they are endangering the lives of other people who end up having to overtake on the inside? How did these people pass their test?
They just seem oblivious to the fact that they are enraging the driver/s behind. Even when you manage to pass them and give them an angry stare they look straight ahead of them...no sideways glance...no look in any mirror...both hands on the steering wheel in the 10 to two position...not blinking...etc. Anyone looking for evidence of extra terrestrial life need look no further. How these people manage to navigate the roads of Britain with one fixed position is way beyond my understandings and they definitely must have some higher power working with them.