Percy had enough of bending to other people, be it Gods or Gabe. The Sea didn't like being restrained, and neither did Percy. It was time to make a change for the better and to be his own person. Different!Badass!Swearing!Cool!Percy R&R

"I quit" Luffy once said, and that was because he had a plan, to use knowledge that no one knew he had to change things forever.