Initially electricity was just used for lighting purpose. But, soon with growth it became useful for several other works, which resulted in it’s use in a different way than just the common light socket.
1920s saw the introduction of two-prong electric plug.
With safety in mind, safer three-pin outlets grew. This new third pin was a neutral supply line connected to earth, such that the fuse would blow if there would be any short circuit which would disconnect the supply.
Later on many countries developed a plug of their own. World now has 15 different styles of plugs and wall outlets. Countries didn’t chose the US standard, thinking it to be unsafe because of it’s unsafe design.
For several decade International Electrotechnical Commission (IEC) has been trying to develop a domestic power plug common to all, but, after fighting several social problems it succeeded in 1986, as it introduced a type N plug to the worlds, though initially no one opted for it. However, Brazil in 2007 became the first country to adapt this type N standard.
This Standard N plug system was chosen as it was safer and also it basically was to eradicate the inconguruous use of variety of plugs throughout the countries. There is no use of so many different sockets.
But, sadly, some countries like Latin-American, African and Asian are still stuck in same varying situation which Brazil was in.
It’s very important to have a common standardized plug N (or another safe and preferably widely used earthed plug system such as F, G or I, for that matter) system in all over the world to eradicate the unnecessary confusion.