“ If mana recovered slowly enough, and mages could pass it on freely between them, the ephemeral force would become a valuable trading commodity on its own.”
“ Faerie foods with unusual effects. Like faerie sausages that turn the eaters into wiener dogs, faerie wines that make the drinker whiny, etc. There's a table in Palladium Fantasy RPG which has a table of ideas.”
“ A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.”