Russell Buckley on Let’s see you answer this one without using Google or Wikipedia: Maybe they just respect the old ways. Everyone used to drive on the left when we rode horses - hence the universal mounting a horse from the left ie curbside. No one stands in the middle of the road to mount a horse.
Napoleon changed this - some say he was bloody minded and some that he was left handed and wanted his sword arm in the best position for him ie if he was riding on the left of the road, he would be at a big disadvantage if attacked by a right-handed attacker riding on his respective left of the road and coming towards Napoleon.
The reason why most countries drive on the right today is obviously the influence of the car industry, especially in the US - which was mainly based in historically French dominated states.
Ok, that's without Google etc, so apologies for any inaccuracies.
John Sinteur on Let’s see you answer this one without using Google or Wikipedia: Well, the only other country in the Americas driving on the left is Guyana, which is indeed a former British Colony, I think that's not a bad guess at all - but no, although there has been plenty of British folks around in history, Surinam has never been a formal British colony. That's not it.