For my own work, I find there's actually only a given quota of 'stuff I actually want to do' on a given day. If I'm not in a good place (health, mental health, etc) this number is much lower than if I were in a good place.
Generally I unconsciously categorize tasks that I remember I need to do* (or that a task list helps me remember) a kind of emotional score relating to their ease of accomplishing, the need to get them done today / sooner vs later, and how big a work slot I feel I have to pack them inside of.
I have noticed that tasks which are perceived as easy or quick to accomplish tend to get fulfilled faster; I can clear the item out of my mental list and it can be squeezed in to moments that would otherwise not be productive.
Tasks with external dependencies (meeting others, scheduling anything at all with anyone else, waiting on external approval processes) are clutter that stuffs up my mental caches, but isn't quite something that I can clear out either.
The inability to clear those things out becomes a type of stress, and creates a negative feedback loop of it's own.
Foreknowledge of those issues, as well as scheduling constraints for doing things, often leads to the estimation that a task which might otherwise be easier (for example if moving fast and breaking things) to cost more (only break things during limited, pre-announced windows).