There is a certain kind of silver-coloured spider who's bite injects an addictive drug into the person that creates a sense of euphoria. Once bitten the PC has a 50% chance of being addicted to the spider's bite and will carry it around with him or her.Long term use leads to serious injury or death.At first the PC will just seem a bit slower or sleepier then normal.
Within a kingdom the prince or princess has died or been killed and the Queen has been driven half-insane with grief.What if one of the PC's was mistaken for the dead prince or princess and not allowed to leave? There would be advantages in accepting the role, but would it be worth it?
If a fighter has a +1 sword that only gives that plus one if he does an exhausting practice routine in the morning, he's liable to ditch the magic sword and just use an old fashioned chunk of steel. Rather than being wore out and need to rest a couple hours before he gets started just in case he needs that plus one, he could just strap on a blade and ride off without having to deal with all the issues. (From Something Agar said)