Yeah, I second the "things which result in later things" statement. If I could sum up the basic approach one should take in exploring the game, I would say never feel like you're over-examining something. In any given moment, talk to everyone around you at least twice, and examine objects at least three times. (Specific hint: The first time you're in the "locker room" learning about the "munitions pods" or whatever they are called, check Zack's pod repeatedly and you will get a Cursed Ring. Of course, you're past that point, but still, future reference!)
Yeah, over-analyze everything, lol.