Your Brain Isn't Storage

David Allen built GTD on one blunt insight: your brain is great at having ideas and terrible at holding them. Every unfinished task and every vague "I should" sits there nagging, eating up mental RAM.

An unfinished task doesn't sit quietly. Your mind keeps poking you about it at the worst moments — in the shower, at 2 a.m. — because it doesn't trust that you'll remember. The fix is almost embarrassingly simple. Write the thing down somewhere you actually check, and the nagging stops.