I first encountered the idea of email validation in Agile Web Development with Ruby on Rails, which I read in middle school. In the book they give an example of

I first encountered the idea of email validation in Agile Web Development with Ruby on Rails, which I read in middle school. In the book they give an example of validating email addresses to show how you could use regex to validate. I wonder if that contributed to the frustrating problem of developers trying to validate emails and not accepting valid inputs.