“ Another real world thing. White tea. Can only be picked two days a year, the two days before the flowers blossom. Could be a similiar plant that...is the deadliest poison known, cure known diseases or psychosis, or a potent herb that just tastes awesome.”
“ What if potions and tonics had negative side effects? Potions of increased strength cause violent tempers, or damage joints. What if potions of dexterity caused tremors, or palsy?
What if they were addictive, and had withdrawal symptoms?
Could someone make a bad batch? No one use the brown strength potion!”
“ The creatures in this dungeon will not become hostile so long as you do not cause any trouble inside. If you provoke them though, you aggro the whole dungeon. If the players are smart, they can complete the dungeon crawl without having to fight anything.”