Being adrift alone and lost at sea. At some point the food and water runs out and clouds can obscure the sun so that you don't even know, in which direction you are drifting. A good Game-master can use this scenario to allow a new player character to join an existing game by having the current players fine the poor cast-a-way. Of the game master can require a moral role to determine at what point the player character cracks and takes drastic action.