How many projects are you on?
I did a count today: I have 52 active projects in my Omnifocus database. Each project has multiple actions associated with it (but I didn’t bother to count them).
Actively filtering all this (planned) activity requires time and commitment. Without the discipline to review what’s active and what needs to be done next, the wheels would quickly fall off.
This is the lot of the modern knowledge worker. Activity has to be self-managed. Having a system helps enormously.