Ja-ja! Yes!
You touched a subject that is in my attention lately: willpower. I kinda believe (not totally convinced by now) that willpower is something limited, like finite every day or in a certain amount of time. If we have something that consumes us a lot of energy/willpower, there is not much room for other things.
For example, I think being on a diet in a stressful period is a lot harder.

As I told, these are open ideas. What is your opinion? Is will power limited or not? Is a good motivation enough to generate infinite willpower?