Star Ocean 2 fan here!
I love the gameplay, skill system, characters, storyline, everything. I swear, everytime I play through it I find something new. Loads upon loads of replay value, so I hardly get tired of it.
Never played 1 or 3. I wont touch 3 because of the storyline, though. Sure, it's different, but not something I could really enjoy.
So, I suppose my obsesstions lie within 2, for now.