Pet hates when driving?  Okay, here's mine:

1.  Being stuck behind an idiot driving a car so slowly despite having a clear road in front of them that you're having to move the car with the clutch, not the throttle.

2.  The aggravating frustration that comes with not being able to overtake the type of people mentioned in Point 1 due to a constant stream of traffic in the opposite direction preventing you from doing so.

3.  People following you so closely that if you were forced to do an emergency stop for some reason they'd go right into the back of your car.

4.  Speed cameras.