What is the appeal of painfully spicy food?

I just failed to stop the burrito guy from putting hot sauce on my burrito, and it is drenched in hot sauce so spicy that it is completely inedible. He was not messing around.

I understand wanting to add a little bit of heat to give a dish more dimension and make it more interesting. However, it seems that in many cuisines, the goal is to actually make the food so spicy that people are actually experiencing physical pain. What is the appeal of this?

Also, I understand everyone has different spiciness thresholds, so I am not asking why some people enjoy food that I consider spicy.