It just seems odd to me that someone is willing to pay a big premium to get a performance car but <£10 increase on a tank of fuel gets them drafting trucks at 56 mph
You'd be surprised at how few people look at what a car costs to run and whether it's worth it versus the alternatives when deciding what to buy.
For many of these people, it will be because such costs are inconsequential and they are happy to absorb them. But for others the lack of research ends up with driving at 56mph or changing cars every 3 weeks at an even greater cost, which also gets ignored.
I don't fully agree that once you've bought anything other than a 1.2 Fiesta you've no right to be bothered about how much money you waste on fuel and therefore there is no need to ever take steps to drive efficiently, but sitting behind trucks is getting to the 'Why did you buy that car?' side of the argument.