1) You cant do everything. The more I advance in my career, the more comfortable I become with abandoning things. It is almost the same feeling as deleting dead code. I also realized that there's a better chance that I will do something if I enjoy it (duh) or if it's not menial. Tasks that are completely pointless still have a chance of being done if they are fun to me. Tasks that are neither will likely never be touched unless I might get fired for not doing them. What's depressing is that it takes some courage to admit defeat and cancel tasks, for some reason. Probably the fomo or something like that. But the psychological overhead of maintaining a pile of stuff is so high. Look at most backlogs, featuring pages after pages of valueless features that will never be done and bugs that will never get fixed. Yet when you propose a simple rule that we should just delete or close anything that had been lingering for more than 1y, people look at you like you're crazy
2) work is hard, and procrastination is real: we are cabled to minimize our cognitive expenditure. I think I can do a max of 1 to 2h per day of hard work, maybe a bit more if it's something I really enjoy, and there's probably a weekly cap as well. Doing something hard is not something I look forward to (don't put that on your resume). So when I pick the todo list, and have a choice between "add this fun feature to your pet project" or "define goals for next year", guess which will be done, and which will be postponed every single time.. . I think the only way of doing these harder tasks is by making them easier, less ambiguous, time bound, more fun, i.e lower the entry cost of the task. That's where some of the value of GTD and such methods resides - by defining a mechanism that transform "stuff" into actionable items. But even that is hard. I'm almost 20y in, yet I still struggle to abide to a strict process.
Work is hard.