There were a several games that left an incredible impression on me as an individual. I think I can narrow them down into this, however.
Phantasy Star II
This was the beginning of the end for me.
I probably had no business playing this game when I was 9 years old, as it had many mature themes. However, I did play it, and I still remember it now with an amount of fondness. Before this game, playing videogames was merely a hobby of mine. They were something to play when I was bored, or when you had friends over. Afterwards, videogames became an integral part of my character. I started to consider myself as a "gamer," and so began my quest to find for more difficult and unique challenges.