Remote work removed three structures at once: the manager glancing at your screen, the commute that drew a line under the day, and the office that physically separated work from the rest of your life. Those structures did real work on your attention. Take them away and the only thing left holding the line is willpower, the weakest tool for the job, and the one that runs lowest exactly when the day is hardest.
The cost is sharper than it looks. Research on knowledge work has long found that after an interruption it takes roughly twenty-three minutes to fully refocus. A phone that pulls you out of deep work a few times an hour does not cost you the two minutes you spent looking at it; it costs you the focus you have to rebuild each time. For someone paid to produce, not to attend, that is the whole job leaking out through a habit.
Most focus apps were built for this audience and still fail it, because they are soft: a dim screen, a banner, a timer you can cancel. Soft tools lose to a depleted afternoon brain. ScreenFine assumes the willpower path has already failed and puts a felt cost on the moment instead.