As well as embracing the DNF, I have recently adopted the NRN (not right now) approach too. I've re-shelved a couple of reads recently that I still want to read, but not right now. It's ok to put a book back on the shelf for another time. Mood reading is much like life - unpredictable.
As long as you don't use the BIWHF approach (burn it with holy fire) for my books, I can definitely understand that!
Are they physical books? If so, do you leave your bookmark in them to mark the soft-DNF? I find it highly instructive to return later and find the bookmark still in there (thinks: Left Hand of Darkness in this particular case).
Sometimes, yes. Depending on how long it takes before I pick them up again, I usually have to start from the beginning regardless.
Oh yeah, I restart too. I like to be reminded where I got to, often when I’ve completely forgotten I even tried!