"You don't need a reason to help people."
-Zidane Tribal, Final Fantasy IX
Throughout the game, Zidane's key trait is that he's a thief with a heart of gold. Many times, he offers to help those who are less fortunate. He is asked why he does this, by both allies and enemies, and each time, he gives an answer similar to the quote.
Xirei said:
"Enough expository banter. It's time we fight like men. And ladies. And ladies who dress like men. For Gilgamesh...IT IS MORPHING TIME!"
--Gilgamesh, Final Fantasy V. The game liked to take itself seriously enough, but that was mostly a lie. It was a lot of campy fun when it wasn't telling a great story.
And then Clash on the Big Bridge plays, you gear up for this epic battle...and he gets his ass kicked.