:electric_plug:British plugs have different voltage and require converters for American devices.
:oncoming_automobile:Driving in Britain means driving on the left side of the road and adjusting to different car parts names.
:train2:Trains in Britain can be expensive, but there are ways to cut costs, like booking in advance or using a Brit rail pass.
:money_with_wings:Tipping is not mandatory in Britain, but some servers appreciate it. Just don't expect the same level of service as in the US.
:earth_africa:British people generally have no issue with Americans and find their accents intriguing.