Want to -- vs -- Should
Which motivates you? I should go to the gym. I want to go to the gym.
It FEELS like there should be a "right" answer. In fact, it "feels" like want to is the right answer. But it isn't... and, more so, there isn't a right answer at all.
There's only a right answer for you. And it will vary from situation to situation.
The trick is not to get your wires crossed -- be clear with yourself about when to motivate with a want... and when with a should. Don't let them flip.
I won't wait until I want to do my taxes (it will never happen). I do them because I should.
For writing projects -- for me -- when they turn into shoulds, no matter how much I love them, I know I'm in trouble. Writing is a want for me.
What are your wants? Your shoulds? Is there a shortcut to see which is which?
And, yes, you can turn almost any should into a want (I do my taxes because I want to avoid penalties) -- but the question is which motivates you -- which provokes action? And, for me, the want of avoiding penalties... well, that's not really why I do my taxes. I do them because I should.