In startup environments there are often significant tasks that go out of your comfort zone (if you're an engineer, you may have to write a tutorial or a script for a video). Those don't typically go on my "pending" list although they are very important to the business, sometimes even more so than dealing with whatever technical situation that might have come up in the last few days.
This is why I have stopped feeling guilty about what I used to call "procrastination". Sometimes you have to avoid your task list and work on the complex things.
This said, the Service Desk / Issue tracking system we develop adopted a GTD-like philosophy in its latest iteration (a pretty significant UX change) and the feedback from our internal and external customers has been outstanding. It helps you keep your head level.