My take on it is simple. When you get that "bite" from a chili pepper, you know that no damage is being actually done to you, so that moderates one's normal re

My take on it is simple. When you get that "bite" from a chili pepper, you know that no damage is being actually done to you, so that moderates one's normal reaction to pain (no real need to run away from the pain if there is no actual damage). However a deeper part of the brain also registers the pain as negative, and as a self defense, causes the release of endorphins to counteract the pain (the evolutionary purpose of which would be to allow you to more effectively escape the current danger that is causing the pain). Our modern brains interpret the endorphin rush as pleasure. Therefore, we seek out hot peppers.