I used to travel quite a lot, and quite often only when you arrive in a new country you remember that their sockets are different and you didn’t prepare for this. This is why airport travel shops carry travel adapters and also why some hotels (the better ones) have at least one outlet of a nonlocal type just in case a customer has forgotten to get an adapter, but needs to, say, work on their laptop without interruption.
A travel adapter that lets me plug a European plug into a UK or USA socket1 is very good ...
