Along these lines, for me, it was the realization that security and money and so much more, are just like every other good. Which gave rise to, "And other goods get better when not produced under monopoly. So, why do we have monopolies in these areas?" And eventually, "OMG we don't need the monopolies."
Mises U did it for me. I had no idea what to expect there. Walked out a different person.