I think you are absolutely spot on. Fear is a key to many failures of human behavior, and I want to think more about that.

Interestingly, many time management systems like Zen to Done and Do It Tomorrow do set up a form of commitments for a day or for a week. ZTD has:

3) plan. Habit: set MITs [Most Important Tasks] for week, day. Each week, list the Big Rocks that you want to accomplish, and schedule them first. Each day, create a list of 1-3 MITs (basically your Big Rocks for the day) and be sure to accomplish them. Do your MITs early in the day to get them out of the way and to ensure that they get done.

Do It Tomorrow has a concept of a closed list in contrast to a todo-list. Every time you go to sleep you compile a list of tasks for tomorrow that you absolutely definitely gonna do. It's realistic to expect yourself to not succeed at too many things, so your closed list might contain only one task. But the fact is, you do only things on the closed list, and not add anything on top of it.

The idea of setting up a commitment for a day, or a commitment for a week, sounds sorta like applying the concept of Pomodoro for a larger time frame. During Pomodoro you aren't allowed to not do the task at hand (which implies you aren't allowed being distracted), and here you aren't allowed to not do what you already planned for a week.