Final Fantasy 9 when I was like maybe 10, if even double digits. Didn't understand how RPGs worked so I didn't understand the concept of STR, DEX, ect... only HP. So when I got to the first real boss in the ice caves I just couldn't figure out why it was so hard. Hated RPGs.
A year later a friend introduced me to Legend of Dragoon. He helped me understand RPGs. Fell in love with RPGs ever since. Eventually came back to Final Fantasy 9 and beat it happily. Still my favorite FF game to this day.