What's all the aggression about?

Sitting in a car is akin to sitting in a cinema, you've got a lovely seat, an artificial environment controlled by air conditioning, possibly a snack to eat, some soundtrack you've chosen, and outside of the screen you have this lovely image of the world.

Then some cyclist gets in the way and your rosy experience is shattered and you have to deal with the fact that you're in traffic and in a grey town, and that people are making you interact with it all.

Point is: Drivers experience a detached and illusory view of the world, and they really hate those that make them experience the real side of it and shatter this illusion.

That's always been my take on it. That they hate externals (cyclists, motorbikes, peds) because it pops their bubble.

You've just identified a Parisian driver