I have driven a right hand drive car. In countries that were/are heavily influenced by the British Empire, such as former colonies, most are that way. When driving in such a country you can't do it by instinct as you would here. You have to actually keep your mind on what you are doing. Additionally, after you have spend a couple of weeks driving on the left side of the road when you return to the US it takes a little while to get back to "normal." It's not hard, you just have to think rather than doing what comes naturally.

In England they drive on the left side of the road. Around here we drive on what's left of the road.