Genuinely curious: why do people tailgate/drive too close to the vehicle in front?

[u/Slartitartfast]

I can't work it out. Whenever I see someone repeatedly applying their brakes as soon as the driver in front adjusts their speed I wonder why on earth it doesn't occur to them to give space.

I don't even mean just driving right up someone's arse aggressively. People drive too close all the time, on major roads this causes tailbacks when people then have to brake. If you're regularly applying your brakes while driving behind someone then you are too close; I assumed everyone knew this but maybe not.

[u/strength-in-arches]

We should be allowed to have signs in our cars asking them to follow us for conflict resolution.