One of the strangest I've encountered is the driving on the shoulder in Texas.
It's been a while since I drove much in Texas, but I mainly saw that done in order to get around backed-up traffic on a freeway and make it down to an exit. But if there wasn't an exit near, they would just make tracks through the grass beside the road and bump off onto the frontage road. In Houston there were lots of places that had permanent ruts through the grass.
In Arizona, DH tried that Texas thing of driving down the shoulder to get to an exit when traffic was backed up, and instead of being lauded for helping to clear the roadway, he was rewarded with a ticket for negligent driving, which was a minor felony. He managed to get it reduced, but he had to hire a lawyer and go to court. "DAYEM, that's jist the way it's done whur I come from!"