"There's too much to do"

This is the objection that feels unanswerable. You're not staying late for fun. The work is there, in quantity, and it has to be done by someone. If you went home at half past five, it wouldn't disappear. You'd simply be further behind.

Part of this is true, and I'll come to that part. But first notice something about the volume of your work. It was too much at thirty-seven and a half hours, which is why you went up to forty-five. It was too much at forty-five, which is why you went to fifty-five. It's still too much. If you went to sixty-five it would still be too much, and you know that. In a job like yours, there's no number of hours at which the work is finished, so it makes no sense to keep working until it is.

The second thing to notice is drift. There's an old quip, first made by the writer C. Northcote Parkinson in the 1950s, that work expands to fill the time available for its completion. He meant it as a joke about bureaucracy, and I'm offering it as an observation and not a law. But you can test it against your own experience. Think of the last working day before a holiday. You had a fixed, immovable finishing time, and a long list. You were brisk. You decided things quickly, skipped what didn't matter, wrote short emails, delegated, and said no to a meeting. You probably got through more that day than in any two ordinary ones. Then you left on time.

On that day the amount of work was the same as usual, and what was different was that you had a firm finishing time. On an ordinary Tuesday, with the evening available as overflow, no decision is forced. The report can be polished because there's time to polish it. You can answer an email at length, and let the meeting overrun. When the day has no end, nothing in it has to be prioritised, and so the low-value work gets done alongside the high-value work and the day stretches to hold both.

Look at what filled your two hours between five and seven. None of it would have made the cut on the day before a holiday. So you didn't lack time that Tuesday. You had more than the important work needed, and drift used up the difference.

Now the true part. Some workloads really are too big. If you've cut out the low-value work and you still can't do what's required in something like your contracted hours, then the organisation has a staffing problem. Your evenings are concealing it. While you absorb the excess without complaint, nobody above you has any reason to know that the job is too large for one person, and every reason to believe it isn't. Your long hours also make things harder for whoever holds the post after you, who'll inherit a job sized for fifty-five hours.

Going on absorbing the overload won't solve it. You need to make it visible, and chapter 17 suggests how. For now, I'd ask you to hold open the possibility that some of your "too much" is drift, and that you won't know how much until the day has an end.