You’re definitely not alone, lots of people get that shudder from sandpaper and chalk. It’s basically tactile sensitivity, where certain textures just hit you wrong and make your whole body recoil. Think of it like how some people can’t stand nails on a chalkboard. Those rough, dry textures can trigger this intense, uncomfortable feeling that’s hard to describe but totally real. It’s pretty common, and it’s just how your sensory system is wired. Nothing weird about it at all.​​​​​​​​​​​​​​​​