[int_19h]

Invidivual countries that constitute the EU today have standardized wall sockets long before EU was a thing. It's unfortunate that they ended up using somewhat different plugs, and if EU existed already when that standardization happened, it would probably have been a single plug instead, as with USB-C.

[jen20]

Italy and Switzerland and France all have multiple variants in common use - all of which are worse than the British standard.