You’re driving downtown, in three lanes of traffic, during rush hour on a Friday afternoon.
Your foot is jumping between the accelerator and the brake. Your eyes are looking out front, but also frequently checking the rear-view mirror.
And you’re in the middle lane, so you’re watching your wing mirrors and turning your head to check the blind spots.
In short, you’re moving forward, but constantly aware of everything that is happening around you, and adjusting how you drive accordingly.
And then…every now and again you’ll end up behind one of those annoying drivers who does none of these things, other than staring straight ahead. These bad drivers act as if they are completely alone on the road, without any regard to anything that is happening around them, with the exception of what’s right in front of their noses.