I can only do this if I don't get too far into a book. But if I've spent a few days on it, and have read over, say, 200 pages, I usually have to finish it. Otherwise I wasted my time. Don't ask.It's interesting how many of us casually put DNF for books in that list.
I think the tendency at one time, when you had to physically go to the library or book store, was to plod on with a dull story because the alternative was nothing to read.
Nowadays a lot of us have a large number of ebooks/audio books, all clamouring for our attention, so we can happily walk away from a book without any regret at not finishing it