An article or blog post by an individual that helped you greatly?

I have been doing some Ask HN posts to collect links to good blogs hosted on independent personal websites and written by individuals. Here is one more hoping that this will help me discover some good and interesting content. What I am looking for:

* Share one article or blog post you read that helped you a lot or made an impact on your life or skills?

* The article must not be one of the LinkedIn-style motivational article that is quite common in mass blogging platforms.

* No links to medium, substack, devto etc. please. I am really looking for articles hosted on individual personal websites maintained with love by individual owners.

* The article or post should not be merely helpful. It should have helped you in reality. Do tell us how the article or post was helpful to you?

So I have two hopes from this Ask HN. To get links to good content. To read some interesting stories about how an article on the web made a difference to your life.