I heard once, many years ago, that people were for the most part motivated either by the promise of reward, or motivated by fear of pain or punishment. Of course, we may be motivated to date or marry by the promise of reward-- spending time with the person we desire. And yet, in other areas, we may be motivated by fear of punishment.

Personally, I am okay with planning ahead and figuring out lesson plans for the week or next, but when I began teaching 17 years ago it was really only about one thing: avoiding pain. Let me define pain. Pain would have been having 35+ ninth graders with nothing to do for 15 to 40 minutes left in the period because my lesson plan finished too early. Therefore, like aircraft wings, I OVER-ENGINEERED my lessons to make sure I would not finish early. Thirty-five ninth graders in the classroom with nothing to do for 30 minutes is pretty much the definition of anarchy.
I planned only to avoid pain. Although, I will say designing full lesson plans to keep things hopping (on my terms) was and actually still is not a bad way to achieve
classroom management (and without that, you leave teaching after 2-3 years)
Today, with thousands of lessons under my belt, it's fairly easy now to know how much everything will take and I can usually time multiple activities in my 57 minute period to within 3-5 minutes. Also, I don't plan now just to avoid dead time, I plan now with questions like: what things should my students know? What lessons will prepare them better for living on their own someday? I plan to help them, at least that's my goal.
Enough about me.
What then motivates my students? There is no single answer. Some of the more motivated ones seem to be driven by that goal of getting into their favored UC school, or the school across the country, that actually has 4 seasons like all the Ivy Leagues do. Others, who should fear punishment, strangely don't seem to from what I can see. I consider punishment as having to retake a class, but it would appear that many don't fear failure, perhaps as they have unfortunately become accustomed to it.
What about fear of failure, as an excuse to not even start or finish? Not really sure what that is, since it's not in my life experience really. But for many, I feel that could be a possibility. Or fear of not living up to a parent's high expectations. Others may have a fear of success, because with success brings change and high expectations, and that too can be scary.
We just had parent conferences for the 4th time this year and once again in a 120 minute time frame I saw just over 30 parents. What I really needed to do however, was to spend 10-20 minutes with about 7-8 of those parents, and not the 2-5 minutes on average that I did. In that short amount of time you scratch the surface without much meaningful interaction occurring.
I'm still learning about these young people. At least now I am beginning to ask the right questions, since it is all about them, and not about me anymore. And that's the way it should be.