Really, just writing about it sets my teeth on edge. My 7-year old daughter did this absent-mindedly today, sparking off that indescribable reaction in me, muscles tensing, nerves taut, whole body wincing as if in pain.
Why do some people react this way, while others turn not a hair? I also get it with chalk on slate/blackboard, fibre-tip pens squeaking on paper, etc.
Is this all in the mind? (It sure doesn’t feel like it!)