It's something I've been wondering about for a long long time. Thanks for bringing up the question. Sometimes my problem-of-the-day is not even that hard but I have near zero drive to finish it, but if anybody comes with an issue, I then feel motivated (up until I realize his/her issue was hard I guess).

I see three dimensions:

- natural pleasure of helping someone

- ignorance about the problem, making it seems easier

- a saturation aspect: my problem has probably something i've been dealing with for days, my brain is full of unanswered questions about it and has no more "space" for it