I've been scared and disgusted by Sephiroth for a long time (I really like Aeris) but seeing this scene and the mako reactor scene when he snaps... Oh, I want to cry and wheep on his tragic story... And when he alludes to Aeris and to Zack's feelings for her it's really like... :'( :'( Aaaah Seph...
I love how we can really feel this battle is a race against time.