A little oyster on the Isle of Wonder cannot sleep because it has a pearl in its mouth. So Alexander reads to him to help him sleep.
The whole game, really. How many boyfriends have you had that, all for you, sailed across the known world, fought minotaurs, saved people from curses, saved other people from being sacrificed/abused, brought your parents back from the dead (so, basically, literally going to hell and back for you), infiltrated a castle, and sent you a nice rose and love poem? Could, admittedly, be construed as a rare positive version of Love Makes You Crazy...
In order to get the magic map to travel between the islands, Alexander has to give up his royal insignia ring. The pawn shop owner doesn't really want to accept a family heirloom, and Alexander comments that he didn't always have a family note See King's Quest III for an explanation, but he really needs the map. The pawn shop owner offers to keep it out of sight for a few days, and Alexander can get it back by trading in a pearl. Heartwarming and Tear Jerker at the same time.
The Golden Ending crosses this with Crowning Moment Of Awesome. Everyone is there, alive and happy. Alexander exposing Alhazred has meant the islands are no longer feuding, Cassima's parents are Back from the Dead, Graham is able to give his blessing, the ferry is repaired so the islands can trade among each other again, the genie is no longer enslaved to a wicked master, and Jollo performs stage tricks in celebration.