There’s a remarkable story in the Talmud that can be taken in many ways, but as one would expect, R’ Salanter points to its Mussar components and draws it closer to home in the process.
We’re told that on the eve of Rosh Hashanah one year — a year of drought — a certain pious man gave a hard-earned coin to a poor person, and that his wife upset him by saying something negative about it (since she needed the money to feed the family). We’re told that the pious man went to spend the night in a cemetery where he heard two spirits speaking to each other (Berachot 18b).
Most of the commentaries are taken aback by the story and go to great lengths to explain it rationally. Some (like the Maharasha and the Ritva) clarify it by saying that the whole incident occurred in a dream. But R’ Salanter made the point that it isn’t necessary to go to that extent to understand what was said and that in fact the Talmud is teaching us a valuable Mussar lesson.
R’ Salanter went on to say that the pious man was reacting to the fact that he perceived his wife as having “upset” — affronted and aggravated — him, which prompted him to get angry (and perhaps petulant). R’ Salanter cited another Talmudic source that referred to someone likewise trying to upset Hillel (see Shabbos 30b) by asking him things that the great preponderance of us would have been upset about and indeed angered by if we were asked them — especially given the fact that the questions were asked right before the onset of Shabbos and made it necessary for Hillel to drop everything again and again to respond.
The point is that our original pious man determined in his heart that he was indeed upset and actually angry by what he wife said to him, and that he’d temporarily lost the humility that lies at the heart of piety (unlike Hillel, who remained unperturbed by the many poorly-timed questions asked of him). So the pious man took it upon himself to heed the teaching that one should “be exceeding humble … (given) mortal man’s end” (Pirke Avot 4:4), and he thus ran to the cemetery where he could take that message to heart as quickly as possible — especially since it was the eve of Rosh Hashanah.
Thus rather than being astonishing, the pious man’s actions were quite reasonable, given what he’d lapsed into and in face of the fact that he had such little time left him to repent before the Day of Judgment.