The one that comes to my mind is BUDDEL.
If you are not paying attention, he will take a dwarven ring from you in every trip. Since he is drunk, if you pay a dwarven ring he will take you to the right location in first try. If you chose to not give him a dwarven ring, then you may end up in a random island.
During the First Dragon event, many people will travel to Okolnir in order to kill Gelidrazah the Frozen, if you are not paying attention, you'll lose MANY dwarven rings, as it happened to me once xD