Jack Sparrow: I have no sympathy for any of you feculent maggots and no more patience to pretend otherwise. Gentlemen, I wash my hand of this weirdness.
Davy Jones: Do you fear death?
Jack Sparrow: You've no idea.
Lord Cutler Beckett: You're mad!
Jack Sparrow: Well if I wasn't, this would probably never work.
Jack Sparrow: William, tell me somethin'. Have you come because you need my help to save a certain distressin' damsel? Or... Rather, damsel in distress? Either one...
Will Turner: No.
Jack Sparrow: Well, then you wouldn't be here, would you? So you can't be here! Q.E.D. - you're not really here!
Jack Sparrow: Did no one come to save me just because they missed me?
Jack Sparrow: We must fight... To run away!
Norrington: I had nothing to do with your father's death. But that does not absolve me of my other sins.
Jack Sparrow: Can't spot it. Must be a tiny thing hiding somewhere behind the Pearl.
Jack Sparrow: Send this pestilent, traitorous, cow-hearted, yeasty codpiece to the brig.
Jack Sparrow: Great! Now we're being followed by rocks.
Elizabeth Swann: It's too late to earn my forgiveness.
Lord Cutler Beckett: The brethren know they face extinction. All that remains is where they make their final stand.
Answer: He agreed to do a job in exchange for eternal life, with a few limitations. If he refused to do that job he'd be cursed until he fulfilled his duties, but that doesn't excuse him from the details of the previous enchantment. He didn't simply choose not to walk on land, he couldn't.
Phixius ★