Mine was finally understanding true self-confidence comes from within. It means knowing your faults and insecurities and saying "fuck it". It sounds simple but the realization was immensely powerful. Of course I did a lot of work over the years (learning about my self, getting over my fear of women, getting over fear of rejection, ignoring what others may think, shutting up my mind). But it dawned on me and I feel so unstoppable.