I have to disagree on this, I did it once by accident. :D
It was however in Italy around 25 years ago and they had sockets from the stone age of electricity, impossible to do it with the current sockets we have in Europe (some countries use different plug/socket system, but most have Schuko).

Ah those, I don't earth them, they get plugged into these: https://www.ebay.co.uk/itm/304939638379 - which also serve as a good place to shove wires into to test things.

They will also go into a UK socket if you open the shutters with a screwdriver in the earth hole first, as many German students do when they come to study here.