Crummy zombies.
What if there was a non-light based monster repellant that you could make, or could be found in dungeon loot? That way, Minecrafters with a spooky little flair like yo would be able to make their emo grunge-pit houses without the fear of the big bad creeper knocking it down.
My immediate thought was a talisman, which would be a good use for paper, or a reasonable thing to expect to only be able to find in a difficult dungeon crawl. Other possibilities could be something like an herbal remedy, kinda like bay leaves to cockroaches (Bay leaves totally ward off cockroaches- betcha didn't know that!). You could even require certain wards for certain enemies so that "Snakegrass root" might keep spiders out of your patio, but you need a Creeper-Crow to keep out the bump in the nights.
And, with the lights down low, I can finally bring my ladyfriends down, and show them that annoying redstone puzzle I made, and they won't see that secret lever in the back by the shadows and figure it out right away.

















