Willpower, volitional action, inspiration
"We can will ourselves to act, but we cannot will ourselves to will" said Albert Einstein. "So, control is largely an illusion," says Robert Lanza.

Equating or conflating control with willpower in the context of achieving set objectives might be relevant. Many feel that while they "want" to achieve, they sometimes lack the willpower, discipline, dedication, or at the extreme, "luck" to achieve their objectives. Let's take a look at how true this is!
Let's start with some questions, and proceed to answer them!
"Is willpower an illusion?" Is it something that can be learned? Or is it something genetically dispensed like physical characteristics? Can we learn to have more willpower, discipline an the like?
Well, simply put, willpower probably is just truly wanting to achieve something. And for that, you must think about "WHY" you want to achieve that objective.
WHY do you want to achieve your objective? Is it for yourself? Or for someone else? What are the real reasons you want to achieve that objective? Is it to get something that you want or NOT to have to have trouble or problems? For example, do you want to be fit and healthy or is it that you do not want to be unfit and unhealthy? These might appear the same, and they are completely different from the perspective of WHY you want to achieve something. One of them is oriented towards pleasure and the other is away from pain. Both pleasure and pain are very integral to human evolution. We have become predominant species on the planet with a blend of accepting pleasure and avoiding pain. Understanding that aspect of WHY you want to achieve your objective will be extremely useful in helping you identify HOW you can, WHAT you need to do, and finally, DOING what's needed to achieve your objective.
A useful way of understanding your why might be to think how you would feel once you have achieved the objective. If is a sense of relief, then most likely your why comes from avoidance of pain, or going away from the negative. If it is a sense of achievement, then most likely it some from acceptance of pleasure and happiness, which is going towards a positive outcome.
If your "why" ( the real reason you want to achieve something) is strong enough and comes from within, you will demonstrate "willpower" through volitional action! "Willpower" is your commitment and dedication you "will" achieve. This comes directly from WHY you want to achieve it in the first place. Whenever you find yourself slacking, or being indisciplined, or not adhering to your own commitments, revisit your WHY. That might help you get the necessary impetus to get going again!
If you still continue to think or say you lack the "willpower" it only means you haven't really identified "why" want to achieve something. Go within and find your why. And maybe you're still thinking, "I have to" rather than "I choose to." Whatever the objective might be, it can be achieved only if you take ownership and responsibility for it. And remember that in every moment there exists a choice. As was said by a learned person, "the ONLY thing a person HAS to do in life is DIE. In everything else, they have a choice." Inspire yourself by finding your "why" and the willpower will be all too visible to yourself and to others. When there is clarity of "purpose" (WHY) then everything becomes possible and easy.
If you're the inspirer, keep inspiring and supporting anyone whom you think doesn't have the willpower or commitment. Help them find their why! And then they will act volitionally and might not need external motivation. Remember, "If it matters to you, then it's up to you!"