The 'leave things undone' tip sounds really good, definitely will try.
What I dislike is when I'm stumped, puzzling over a bug or the correct implementation for a complicated feature. It's not always possible to resolve these situations by the end of the work day and they tend to nag at me through the evening. I don't like that and try to avoid it, rather than deliberately create this feeling ("leave things undone") as some sort of trick for motivation.