Maybe it's a British Thing Pt. 2
Back when horses were the best form of transport, carrying a sword was not seen as dangerous and eccentric, and most normal people were right handed, people started to chose a side. To drive on. I can say with no historical fact or reference, and based mostly on the 5th grader who edited wikipedia, that the UK started to drive on the left because they wanted to be friendly and shake right hands, or wanted to be able to draw their swords without any interference when riding past each other. Reasons for driving on the right are even more fraught with inaccuracy and range from Napoleon's left handedness, to reduce fights among marching armies, and just plain to get back at the UK as one last act of defiance. I prefer the Napoleon idea, especially has France later owned a large chunk of the US and Canada, and maybe it just filtered through all of North America. Who knows?! But back to the point. I mean, to the point in the first place. They drive on the left here, which takes som...