Have you ever gotten a piece of the bottom of a banana or part of the peel that gets stuck to it in your mouth? do you know that feeling, behind the teeth, worse than fingernails on a blackboard. I've gotten that same feeling, though milder, occasionally with sweet potatoes (not sure if it was the very tip, or if it was going bad) and also occasionally with certain brie skin, maybe old. They all feel the same to me. it's just a curiosity but do they have something in common, and am i the only one to notice that? It's extremely unpleasant.