Why even have a productivity system (such as GTD) at all? There are two reasons:
- We need the ability to prioritize and sequence tasks
- We need the ability to defer tasks without forgetting them
All of this flows from having more things to do than we can do immediately. Since you can’t do everything at once, you need an easy way to identify what is most important and sequence tasks in order of importance.
And, since you can’t do everything at once, you need an easy way to put things off to another day or time, without forgetting them altogether.