Angeal, Zack and even Genesis inspires more especially with that loveless poem. While Sepiroth has that entire falls apart from the seams thing and instead of trying to figure things out he instead decides that his gona blow up the planet while killing bunch of people along the way, i can't help but to think there was also some strange need to be superior to everyone else style complex there that not even a mothers love could fix granted Hojo messing with things on the background certainly don't help with mental stability. So Sephiroth was dealt a rotten hand but instead of playing it trough he folded and tried to flip the table.