Is it easier for an American to adapt to British lifestyle or a Briton to adapt to American lifestyle?

Both countries share a lot of similarities. Let's look at the social landscape of everything though. I know Briton is more expensive. Whether or not you'd make enough money to compensate for that is debatable. Do you think it'd be easier for Brits to adapt to driving more then using public transportation? And driving bigger cars on the opposite side of your cars and roads? What about adapting to the education system if you are a teenager? Or the health care system? Or just the people in general?