Get the Seal Piece at the Water Slums. If you played Jak II, chances are you've played this mission. And hated it.
Water Slums at night screenshot
With a passion. You've probably screamed every curse over the Moon, broken controllers, or even bang your head off the wall over this mission. Now, what if I told you there was a way to beat it? This is more of a trick than a glitch.

Before entering this mission, you need Dark Jak. Start the mission, then go Dark Jak. Then, jump into the water and use Dark Bomb. You know that annoying turret thing that kills you when you go into the water? Dark Bomb will KILL that thing. Then, jet board to the goal, and this mission is cleared. And, your controller will live to see another day.