For me it was the first RPG I ever played, D&D3.5. After getting home from that game I immediately started thinking about making my own game, eventually finding that there was a whole universe of game systems that are not d20 based.
Another example is Burning Wheel, after hearing great things about it I bought it and sat down to read it from front to back. When I finished I realized that I could not remember a single thing that I had just read. It was in English, the words did form complete sentences, but not a word of it stuck around in my head. Not sure if it is me or if the ideas were just so obtuse that my brain just flushed them rather than waste storage space.
^2
Another example is Burning Wheel, after hearing great things about it I bought it and sat down to read it from front to back. When I finished I realized that I could not remember a single thing that I had just read. It was in English, the words did form complete sentences, but not a word of it stuck around in my head. Not sure if it is me or if the ideas were just so obtuse that my brain just flushed them rather than waste storage space.
^2