Motivation is that missing shield of willingness. It could easily defend against the enemy of procrastination and its mysterious force that delays the completing of tasks that need to be accomplished by a certain deadline.
And I'm glad it's called "deadline" instead of "lifeline" because that's what it is in many cases - a dead line. Artificially drawn with no real life. No life means lacking love. Then, the illusory battle ensues. That play is interesting too. But where there's love, there's no dream of motivation. As for our purpose, maybe that's why it's been said to do what you love or work is love made visible.
Until then, it is helpful to understand other myths of motivation. For example it's often assumed that others succeed because they are highly-motivated. Well, the average American hits snooze 12 times each morning, and I was relieved to learn that one of my favorite prolific authors still needs to force himself to get started with writing each day after 40 years.
Objects at rest tend to stay at rest unless acted upon by a force. It's totally normal to need a little force to get going. This generates momentum and that might be a more useful concept, especially with its root word "moment" - a very brief portion of time associated with opportunity.
(Music by Lee Rosevere)