Here's what I don't understand about roundabouts: You're waiting your turn to get into the roundabout. Cars are coming into the roundabout in a steady stream from the right (or left in countries where they drive on the right). So how do you get in? In my driver's education in Norway I learnt that as soon as you're inside, then cars not yet inside will need to yield. So if you just creep slowly across the line then the oncoming cars will eventually need to yield. However, here in the UK I've learnt that this is not the case. As long as there is a steady stream of oncoming cars like that, it doesn't matter that they aren't yet inside, you just have to wait, thereby defeating the whole purpose of roundabouts, which is to keep the traffic moving. As long as you're in the stream like that, you only need to worry about cars coming from the right (or left in countries where they drive on the right), and again it doesn't matter if those cars are inside the roundabout or not.
Seems crazy to me, but what do I know!?