I genuinely think that due to motorway driving not being on the driving test (yet!) , there is a whole host of crazy styles on the motorway based more on people's insecurities than anything else useful. How many folk actually read the motorway section of the Highway Code before setting out the first time? I wouldn't expect them to, not a criticism, but you can easily see how strange styles and approaches can come out of pure ignorance.
I've heard the following reasons for middle lane driving:
• "the left lane is used by lorries and is therefore full of ruts. My car drives smoother in the middle lane".
• "it's safer for me to drive in the middle lane, than start in the left lane and have to change lanes every five mins".
• "Everyone else does it, I can't see what the problem is."
• "the left lane is for lorries and heavy goods vehicles".
None of them are based on the Highway Code imperative, it's all based on what works for the driver above all else.
The most frustrating thing I see on motorways is when a German "premium brand" car/premium SUV comes onto a slip road, changes dramatically across three lanes (narrowly missing folk) to park themselves into the third or fourth lane, then steams off and stays in that lane as if it's "premium cars only".
So much of this I reckon is down to the British psyche of not wanting to be in the "paupers" lane, and just get everywhere as quickly as possible