In June 2015, Max Howell posted on Twitter: "Google: 90% of our engineers use the software you wrote (Homebrew), but you can't invert a binary tree on a whiteboard so f*** off."
Howell created Homebrew, the package manager used by millions of developers on macOS. Despite building software that Google engineers use daily, he was rejected for failing one data structure question.
This tweet became the most referenced criticism of tech interviews ever. It sparked a global debate: Does inverting a binary tree on a whiteboard predict job performance?
The interview process persists despite this.