I hate pencils, chalk and chalkboards.
I will never forget the first time I took the SAT, it was in a really noisy room. The desks were those really old desks with loose wooden tops that would squeak loudly every time someone moved. That, and the sound of the pencils scratching on paper, were so loud it felt like the pencils were scratching right inside my head. I couldn't concentrate and I got so frustrated, I was afraid I might fly into a rage. I kept looking around wondering why the noise wasn't bothering anyone else. That was still several months before I figured out I had ADHD.
I can't stand to write with a pencil. It makes me feel like my skin is crawling all over. Even worse to hear an entire room full of pencils scratching.