Modern work has no clear edges anymore, so you need a real system outside your head to stay in control and calm.

• Work today rarely has a fixed end point, unlike simpler tasks from the past — it just keeps expanding.
• Trying to hold everything "in your head" causes stress, since your mind is bad at reliably storing open tasks.
• A trusted external system frees your mind to actually think and focus, instead of trying to remember things.
• The goal is a clear mind and a feeling of full control over everything you need to do.