You're making it too simple. Cecil wasn't cold in the beggining, he was a villain. And he had regrets for attacking Mysidia. Squall was merely a dumbass.
Watch my car when you get out of yours.

Indeed, Squall is a retarded self pitying jerk, and I find it hard to believe all those people stuck with him that long.

Cecil was never really a villain though, he took the path of the Black Knight as was instructed to him by the King, and had no idea about any of the ''King's'' intentions nor of his actual persona.
Cecil felt great shame at what he did, and decided oppression much early in the game.

And Seifer's just an idiot.