3 a (1): a usually sudden manifestation or perception of the essential nature or meaning of something (2) : an intuitive grasp of reality through something (as an event) usually simple and striking (3) : an illuminating discovery b: a revealing scene or moment
The word, of course, is epiphany. My first was the "simple and striking" realization that I was in a manipulative religous cult. The second was the intuitive grasp of reality that there is no supreme being.