Alright, at the end of KH2, when you defeat Xemnas with Donald/Goofy/Riku, right before xemnas dies sora says:
"There's more to a heart then anger and rage, don't you remember?"
And Xemnas replies:
"No, I don't"
However, in Twilight Town, Saix says:
"We remember what's its like to have a heart"...