I am with you on this one. I, for my part, cannot stop unless I finish some logical subset of the work. Leaving the work incomplete or with bugs would make me sleep worse, and I would spend lots of time the next day trying to understand what I was trying to achieve. Even more so in hobby projects, where I might come back in a couple of days or weeks.

What I do, though, is leaving a TODO where I think I need to continue the next time. Works wonders for me.

In the end, I think it is about leaving some kind of an "anchor", but the exact kind depends on your personality I guess.