What is the best article what you ever read about Ruby?

There are so many discussions these days on all channels about so many topics that I feel the need to immerse myself in reading some good articles about Ruby and all.

Thus, inspired by Jeremy Smith let me ask you a question:

or

What is the best article you have ever read about Ruby or Rails, one that influenced your way of writing code or maybe the way you think about Ruby or Rails? 

Please reply in the comments here on the ShortRuby website.

This way, all of us can see all recommendations.

I will love to gather a list of the articles you are suggesting.

PS: I plan to publish a question or announcement in this Community section once per week (but not every week).

If you don’t want to receive them, you can disable these specific emails by accessing manage your subscription section. I also added here a step-by-step guide about how to do this.