Jenson Button's struggles in his McLaren have been one of the defining issues of this season so far.
Button was second in the championship in 2011 but this year, starting from the fourth or fifth race, he has struggled - and he doesn't seem to know why.
The answer is tied up with another of 2012's central themes - the difficulty many teams have had understanding
how to make the new Pirelli tyres work with their cars.
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“Button is not the only driver whose natural style is to turn in on the brakes. Ferrari's Fernando Alonso, among others, is another one. But he has adapted”
Button has a very particular driving style and so far he is having trouble making it work with this year's Pirellis.
We'll come on to the tyres in a moment, but first let's compare Button's driving style with Lewis Hamilton, his McLaren team-mate.
Most drivers of high-performance cars rush up to the corner, stand on the brakes at the last minute, 'stop' the car, turn it and then get back on the throttle. It's exactly what Hamilton does.
Button, by contrast, will brake more gently and turn in a little earlier while simultaneously braking - something the Pirellis are not great at - before taking more speed into the apex of the corner, and be gentler with the throttle on corner exit.
He makes a more blended corner, and it means he needs a car that is balanced for a longer distance mid-corner.
Button's problem has been getting the right amount of grip from the tyres. It's not a unique problem for him, but he has probably been suffering from it more than most.
This year's Pirelli tyres are very different from last year's.
They have been deliberately designed to have a narrow working-temperature window, the idea being to make it more difficult for the engineers and drivers to get the most out of them.
What happens is that the grip will continually improve as the tyre gets towards the working window. But if it goes above it, the grip level deteriorates. So there is a sort of artificial on-off switch.
In qualifying, the difficult thing is to get the front and rear tyre temperatures evenly balanced. It's easy to get the rears up to temperature simply by spinning the wheels. The fronts are a different matter.
Many of the teams will have been playing with the tyre blankets - which heat up the tyres before they go out on to the track - to try to solve this.
It's not easy, because how the blankets are used, at what temperature, and for how long, can have a massive effect on the behaviour of the tyres.
But that can only ever be part of the story. How the driver drives the car out on the track is at least as important.
Button's season in downward spiral
Hamilton's style - braking late and hard - is one good way of getting the front tyre temperatures up.
Being nice and gentle on the tyres, as Button will naturally be, means you don't get the temperature in these Pirellis, and his desire to turn and brake at the same time is counter to the way the tyres want to be used.
Button is not the only driver whose natural style is to do this - Ferrari's Fernando Alonso is one of them. The key difference, though, is that the Spaniard has adapted.
Whenever I watch Alonso on the track, I see someone who modifies his driving style from lap to lap.
He has done that throughout his career, adopting different driving styles depending on the needs of his car. What's more, he can do that within two or three laps.
A lot of people do that, but I don't think Button does. He has his way of driving and that's it.
That's not being critical - it's just the way it is. Rubens Barrichello was the same. Some need specific things; others adapt.
Button's season so far
Throughout his career, Button has been among the very fastest of drivers when he is in a car which reacts well to his driving style.
But when he's not happy with his car, he has been far less effective. He's not as adaptable as some of his rivals.
Solving Button's tyre problems will not be easy - but there are things McLaren could do to make life easier for him.
If they would focus on getting a car that reacts better to Button's characteristics, Hamilton could still use it. But if they build a car that reacts to Lewis's characteristics, Jenson can't use it.
Some might argue that the tyres should not play such a big role in the outcome of races, or individual drivers' careers.
This is an argument that has been used this year in another way.
The fragility of the tyres means drivers always to some extent have to drive within the absolute limit of their cars. Some argue that cheapens the sport and reduces the difference drivers can make.
I don't agree, for two reasons.
if you look at what Alonso has achieved this year in a car that is nowhere near the best,
it's obviously completely untrue to say driver skill is not making a difference.
Equally, though, is driving within the limitations of your equipment not part of racing? I've seen it through many years - think back to the 1980s when there were fuel restrictions. It's part of the discipline. I'm not sure it's ever been different.
F1 is a team sport. The driver and the team work together to make the car work as well as possible and then it's up to the driver to get the most out of his equipment in the race.
Part of the reason some of the smaller teams have featured at the front this year is that it's not always the big teams who get this right.
You could go to a track with the Red Bull and not have it set up properly and be slow. Get it right, and it's quick.
This year, the lap-time difference between the cars in qualifying and the start of the race is about two seconds more than it should be, taking fuel weight into account.
For some drivers, it is more than two seconds, for others less. For me, that difference is determined by which teams have got their cars set up best and which drivers have worked out how to drive within the tyres most effectively.
Is that not what F1 should be all about?