I have never stepped on a UK variant, but I have stepped on a South African 3 pin plug (our prongs look the same, bigger one in front but they're all round).

Stepping on Lego hurts; stepping on a 3 pin plug with for example the middle of your foot destroys a part of your soul.

At the very least the Lego just cuts you, but the plug feels as if it destroys some of your nerve endings.

Ring binder with the clasps opened.