system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: Why do different countries have different power outlets? Is it on purpose?
gpt
Countries didn’t all develop their electric grids together, they were slapped together independently in the late 1800s and early 1900s.

Eventually the entire developed world was electrified, but you had a problem at the borders - they hadn’t all selected the same voltage and frequency for their grids.  Some had picked 50Hz, others 60.  Some were at 200V, others were at 110V.

Plug in a device that’s expecting the wrong flavor of electricity and it might explode.

Rather than tear down their entire grid and start over, countries just made sure their plugs were unique so you can’t plug in a Russian toaster in Boston and burn the house down.