Endearing characters, epic fairy tale story book adventures, drama, tension, tragedy, love, hate, friendship, betrayal, hope, loss, sacrifice, etc. Good RPGs just move me.
After 100+ hours and its over and I'm sad for several days that its not a world I can visit and meet and just hang out with those characters in real life. That is what a good RPG does to me.
I want to be there when Cecil overcomes his past, I want to be there and share the sorrow when Palom and Porum go to Baron. I guess I like having my emotions fucked with by a interactive story, because honestly I'm not an emotional person at ALL in real life, I'm actually quite the sociopath. But for some reason when those slow tragic orchestra strings fade in and somebody I've grown attatched to sacrifices themselves to save the group I get soft and teary. I see it coming too when that person starts taking selflessly and the music either stops completely or plays a slow sad melody, and a I'm already feeling chills and thinking No...No....omg no ...
Same thing with massive plot twists and revelations...such as "we arrived at what is said to be the resting place of God that had been previously resting deep in the ocean for eons...it appeared to be the hull of a colossal spacecraft over 10,000 years old..." I got full body numbing chills just typing that even now.
Love me some tragedy.