When I first drove in the UK, I was surprised how natural driving on the left side was. I was expecting it to be a huge problem, but it took me only half an hour in real traffic to get used to it. The only problem I had was that you can't shift gears and control the left/right signals at the same time. Normally, I can turn the signal on with my right hand and switch gears with the left hand, so it's not an issue. When driving in the UK, I needed to signal turns in advance, but that's probably a good thing.