Iritis/uveitis - My cornea detached due to the heavy pressure inside my eye. The most painful thing EVER.
Kidney stones - Close second
Motorcycle accident at highway speed that jammed gravel into my cranial cavity and left me looking like watermelon-head for 3 months - I’d still rather have this than kidney stones or iritis…
People said the exact same thing about reddit being only good for technology enthusiasts and porn in the early days.
In my experience that is just how it goes on the internet. Nerds, furries, and porn collectors, are the early adopters for most places. The normies follow along years later.