For me: I only do the "activities that I can't help but do" or the "goals that I can't not reach"
The inputs that I can't not do, and the outputs that I can't not have.
This is a good way to simplify things. I have so many things I want to do. So I ask - am I so compelled to do this certain activity that I can't help it? Or, am I so compelled to get this certain outcome that I can't not make it happen?
If you're struggling with too many things, it's a helpful filter. And you can further filter by asking 'and will that remain true for the next X weeks/months/years' - i.e. was it something that I couldn't not work on 5 years ago? If so then it'll probably also be a can't not 5 years from now.
If you're not struggling with too many options then I don't think it's a good filter, but if you are then it's helpful for stripping your list down to the essentials.