I always kinda wonder about this. Why? If you're alone on a highway what difference does it make to cruise in the left lane vs the middle?

"What if I'm in the middle lane and come up on someone slower than me?" You hop left, pass, and then hop back to mid.

"What if I'm in the left lane and someone comes up behind me going faster?" You hop right, let them pass, and then hop back left.

Feels identical. So why so many people cruise in the left is kinda confusing to me. Just going against the rules of the road for funzies?

Personally I zone out so I cruise in the middle in case I don't notice the person in my rear view. Also easier to notice coming up on someone ahead of me than some speed demon in the rear view.