Why have a passenger that is there only to make the player's some money when you can screw with them at the same time? d66 Passenger's Ulterior Motives gives you the ideas you need to make every single passenger memorable and a jumping-off point for adventure.
22 Falsely accused of a crime, doesn't believe they will get a fair trial
35 Mentally unstable conspiracy theorist wants to prove slave ring on ship
62 Smuggler, wearing stolen goods on their body for the whole trip