In the pathfinder game I used to run before I fell in love with Dungeon Crawl Classics, I always kept a stack of pregen NPCs (or characters that belonged to people who moved away) on hand for people who want to try a game or two without committing to being a character. One of those guys was a sailor dude. While he was played a couple times, he mostly stuck around to pilot the boat for the party with his Profession-Sailor checks. In my game, the party came to a remote region that was in the midst of a festival where they were celebrating the harvesting of a key ingredient to their local liquor, and everyone was getting fucked up. While the NPC was passed out, they sold his boat from under him because they'd recently acquired a magical boat that could shrink down to fit your pocket, and when fully sized was piloted by a phantom crew. They were able to convince the NPC that he traded it for some Elven cocaine (Pathfinder is kinda broken in that you can min/max your way into having a +20 bluff bonus at lower levels) and then went on an adventure where a really autistic wizard teleported them to the other side of the continent, leaving said NPC behind.
We thought that was the last of him, but I joined a 5th Edition campaign and the DM said he needed a sailor. Since a couple players in this new campaign were from the one I ran, I decided to make this guy with the backstory that he got really bummed out after being ditched, so he got so wasted that when he came to, he realized that he somehow drunkenly wandered not only into a different plane of existence, but also a completely different ruleset