There is a liberating side to toothbrushing problems: the stakes of any given unit of effort are low.
With diploma problems, if you blow it, you really blow it, with often irrevocable long-term consequences. All of your effort is building to a high stakes climax and if you miss your shot, that effort can all end up wasted. It's videogame permadeath mode for life.
But with toothbrushing problems, you can have an off day and usually make it up today. Of course, every day's effort does matter. You can't make every day an off day. But I find something very comforting about problems where some random variance in my output does smooth out to the mean over time.