I admit that it does "work", to some extent, but I thought I'd also post a contrasting opinion and observation: there are also people (like me) for whom arbit

I admit that it does "work", to some extent, but I thought I'd also post a contrasting opinion and observation: there are also people (like me) for whom arbitrary structure is a complete turn off. If I feel manipulated or like there are arbitrary restrictions or peculiar structure to things that I can't justify, what you're liable to get is disengagement, leaving, etc. From a survivorship bias point of view, you might find that the kind of people who stick around and show a positive effect are those who react and apply themselves positively to structure + externally set goals + feedback. That positive bump might be because the entire set of people who leave your little experiment or disengage as a result. I suggest this was/is one of the reasons I have problems with formal education environments, much modern game design, and an general dislike of bundles and sets in products. Again, that's not to say it can't work for your use case and temperament, but be aware you're also likely going to turn some people off, and they'll tune/ opt out altogether if that's any concern to you...