When I was in yeshiva in Israel (Kerem b'Yavneh, 20 years ago), mid-December was the time when hundreds of young men spending their "gap year" learning in Israel toppled over the edge of burnout.
Sometime around November, a combination of 1) studying mussar, 2) experiencing peer pressure 3) sensing they had a rare opportunity to learn and 4) escaping home supervision reached a tipping point and students began learning until 1 AM or later, taking few breaks other than to collapse into bed. Calls home were reduced, the "Out Shabbos" or Shabbaton was a nuisance, showering became a special pre-Shabbos experience, and relatives' visits certainly did not warrant leaving the yeshiva campus.
I don't know that things are still so, but in those days this phase would last for weeks, and then burnout would set in. The pace would prove too much, and most guys would drop into bed for a few days before coming to some sort of equilibrium. I have fond memories of that time.
One of the main drivers of the whole experience was the mussar I mentioned above – messages focussed on convincing us to take advantage of every moment. One of my favorites was the Rosh Yeshiva, Rav Goldvicht zt"l's answer for a question raised in Tosafos Kesuvos 17a מבטלין:
The gemara there seems to conflict with a story involving Rabbi Akiva. The gemara says that one who is learning Torah should cease his study to take care of a funeral. On the other hand, a story (recorded in Masechet Derech Eretz) presents Rabbi Akiva saying, "Once, early in my time serving the sages, I was walking along the road and I found a meit mitzvah [a corpse without anyone to take care of it]. I took care of it, transporting it 4 kilometers until I reached a cemetery and buried it. When I reported this to [my mentors] Rabbi Eliezer and Rabbi Yehoshua, they told me, 'Each step you took was like spilling innocent blood.'"
What was wrong with Rabbi Akiva's actions? Don't funeral needs override Torah study?
Tosafot there asks the question and offers two explanations, but I recall the Rosh Yeshiva zt"l explaining it in his own way: Rabbi Akiva was 100% right for taking care of the meit mitzvah. However, being right doesn't change the fact that he had lost many hours from study, and he would never be able to re-coup those hours. Even were he to add hours from other activities, those would be hours which he could always have added. The Rabbi Akiva he could have become would never exist; he had murdered his potential self.
That sort of thinking can drive you crazy, I know that, but it's so blunt, black-and-white, unvarnished and unapologetic, that I find it compelling. It's true – being "right" doesn't mean you get what you want – and it's demanding. I loved, and still love, lessons like that.