I guess I was obsessed with FF7 when I first got it. I was always thinking about it and talking about it at school. I was really upset when the 3rd CD broke and I couldn't continue the game (and nobody would lend me their CD). It wore off pretty quick, though. I never experienced the effect again and no longer have such feelings for the game.
The series as a whole I have not been obsessed with. The only other Final Fantasy that has ever interested me enough to have me playing it for more than 10 minutes is IV.