The eight-hour workday is an outdated and ineffective approach to work. If you want to be as productive as possible, you need to let go of this relic and find a new approach.
The eight-hour workday was created during the industrial revolution as an effort to cut down on the number of hours of manual labor that workers were forced to endure on the factory floor. This breakthrough was a more humane approach to work 200 years ago, yet it possesses little relevance for us today.