“ You receive a vision of a rooftop 'somewhere close by', where a rare moss grows; in the vision, you know the moss is suitable for greatly enhancing the effects of certain types of potions. Now go and find that rooftop. Don't fall off. (Of course, rooftop runners *will* be taken for miscreants by the local City Watch....)”
“ 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.”
“ Small village tavern specialty of the house is fresh cow blood mixed with milk. For each order they go out back and actually draw blood from a cow by puncturing a vein in it's neck. Fresh blood brought to the table where they poor milk into the glass of blood in front of the customer so they know how much blood they are getting.”