system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does blinking take me almost no effort at all, but winking forces multiple muscles/areas in my face to move oddly that aren't even near my eye (i.e. side of my mouth being raised/lowered)?
gpt
The sequence of movements and the muscles involved are the same group of muscles that are active when something's in your eyes. You are not winking but using those muscle groups separately (one side only) to express yourself. It has to do with what nerves are supplying those areas and the nuclei of those nerves. Closure of the eye lid and movement of the muscles are done by the same nerve (Facial nerve). Hence the effort.

It is also a movement that is almost an instinct because you have used them before even as an infant when something gets into your eyes. So kind of like muscle memory but for the wrong task, but it still works at expressing so you keep using it. Practice hard enough, and winking will be effortless. ;)