Cloud (during the highway chase): "Out of gas!? Not now... Tifa forgot to fill the tank up again!"

Tifa: "Dilly dally shilly shally... wait, that sounded totally stupid!"

Cloud (answering the mobile phone): "Hey, sweetie, what's up?"

Sephiroth (after Kadaj turns into him): "Oh no! I've been gone for two years, and when I return, the first thing I see is Cloud lying on top of me!"

Aeris: "I'm so insulted! I was the main character of FFVII, and now they won't even show my face anymore (except for that one scene)! I got so little time on-screen..."

I heard something like this somewhere:
Cloud: "Rufus? Is that you?"
Rufus: "It is I."
Cloud: "But you died! The whole Shinra tower collapsed!"
Rufus: "... I dodged."