What kind of driving habits do other people you know have that make you nervous?

I know a person who'll PRESS THE ACCELERATOR if he sees someone brake in front of him. "It's just so that I can get closer to them" ok well why exactly would you want to do that if you see that they're braking? Nothing wrong with coming to a slow stop if there's some distance between you and the car in front.

Also, people who just generally don't keep their distance between them and the car in front.

I know everyone has their own driving style and I shouldn't backseat drive, but I think I also have the right to call out driving habits that I think are genuinely dangerous.