For me, it's because the thing I'm doing right now is boring, and doing some other project instead (a) seems more interesting by comparison and (b) lets me conv

For me, it's because the thing I'm doing right now is boring, and doing some other project instead (a) seems more interesting by comparison and (b) lets me convince myself that I'm still being productive. When I'm not busy, I can play a game or read a book, and those are way more entertaining than a new project, even a relatively interesting one.