Sometimes when I'm feeling particularly role-playish I will play a song for the quest NPC that comes in the overland encounters - particularly the "pilgrim". most often it's when I'm waiting for nightfall in the skeleton encounter and I want to get more nightshade. It would be nice if they would walk over to me as if they are listening to my performance. Maybe dance a little, even if it's just the little "dance" you do yourself when playing a song. I could see some animals do this also, but maybe not the dance.