How about: as a commitment mechanism, a small but nagging amount of discomfort related to your procrastination on a measurable task. I'm picturing this working something like the need to pee, with the difference that it resets at night: the discomfort could build throughout the day and instantly be resolved when you completed the task and reduced as you work toward the task.

For instance, if you committed to exercising a certain amount, accelerameters could estimate physical activity. for every step you took, your discomfort would decrease and for ever hour you sat on the couch, your discomfort would grow.

Possible commitments this would work with: exercise anki decks habbitrpg points spend a certain amount of time talking per day (for the recluse/introvert trying to train social skills)