Planning an unfeasible list of tasks to achieve on a certain day will most likely end up being counterproductive. It’s not by planning a ton of tasks that you’ll get to do them all. Not only that, but since even if it would never happen, you expected it to do so, you’ll feel as if you’ve somehow failed.
That’s why managing your expectations is so important. Planning alone doesn’t get things done. You need planning sure but don’t overplan.
How would you rather feel at the end of a day? Feeling bad about facing a failure, or motivated since you’ve managed to go through what you wanted to do? Which one affects how you work in a positive way?
I think it’s safe to say that by making it achievable, you’re motivated as opposed to pressured (and stressed) to work. Planning something isn’t the same as doing it, with that in mind create the environment, and mood, that makes it easier to commit to your work.
As always these are just my own thoughts. But I’ve learned that at least to me, managing my own expectations is crucial to being able to motivate myself.