What is something that was pretty influential but is often forgotten or even undermined despite it's importance?

https://ani.social/post/2681813

What is something that was pretty influential but is often forgotten or even undermined despite it's importance? - AniSocial

Vaccines. the original against smallpox was revolutionary, probably one of the most important discoveries of human history. Smallpox was a horrendous disease but we found a way to save the lives of millions of people

And know we have outbreaks of diseases like measles because the vaccines were so effective that people starting to believe that the disease was not so bad and that the risk of the vaccine was greater than the risk of the disease 🤦‍♀️

I’m so sick of people, and their bullshit
If only there were a vaccine for that, too.
There is! We need to inoculate them with books.
That only works if they can read or are open to changing their mind. These kinds of people can’t, generally.
You can also “open someone’s mind” with a book launched at sufficiently high speeds