The Infiniteness of Meaning
Spiritual crises are incredibly powerful. Especially nowadays, where the outrageous meaninglessness of pretty much everything in mainstream culture can be something which just creates an unpleasant gut feeling at first, maybe goes along with health problems, but all pointing towards what a heavily unbalanced media and politics are selling to us. A life trapped in routines, with the crushing thoughts of "but objectively, everything is fine in my life, so why am I crying?".
Also as the current mainstream education systems are incredibly dehumanizing and plainly soul-crushing. Students repeating completely pointless knowledge regurgitated by incompetent, unreflected teachers. But the teachers are not to blame, they are just followers as well.
Humans are animals striving for the Divine. Not as in the Christian God, or Muslim Allah or any other personified figure purely invented for mass control and mass manipulation. I mean what Rudolf Otto called "the Holy", the subjective religious experience and, eventually, in the context of the "enlightenment", the concept of meaning.
The Divine and "meaning" are identical. There is no meaning in anything, except for when you believe in it. Belief in the meaning of life is nothing objective, it's an active decision you make. If you get rid of this drive to consistently manifest the belief in meaning, you break down.
The transition from finding meaning in external things (e.g. Gods from institutionalized religions, money, work, validation from others etc.) to generating meaning from within is the most powerful transition in one's life. It is deeply vulnerable, a bit like a little birdie jumping out of the nest where it grew up for the first time. It means that you're getting wings, that you're freeing yourself from the control others have over you, because you stop believing that anything or anyone else can give you meaning. It's like a new language to learn, a way of being where you question everything, except for one single thing which you forbid yourself from questioning: meaning itself.