I have noticed that S&D can in and of itself be damaging. One day I was sitting on hold with a telephone call, and I started to pull up a strand of hair so that I could see it for a bit of S&D. It was pretty much stuck to neighboring strands, and as I pulled, I saw the ends of a hair pull apart. Of course, maybe it was already split, but it looked like it tore apart because I was pulling in opposite directions.