We can explain that it is the human brain's response to pepper stimulation.
When capsaicin comes into contact with the nerve endings of human mouth and tongue, the pain will arouse the nervous system and make it carry the worst message-fire! Fire! Come to the brain. The warned brain orders the body to enter a state of high operation: tachycardia, aggravated nasal obstruction, mouth full of saliva, accelerated gastrointestinal peristalsis, and profuse sweating.
Psychologist Paul Lokin said that because the human body has the instinct to protect itself from chemical substances, when the human brain senses that the body is hurt from outside, it will automatically release a natural analgesic-endorphin. Since chili does not really harm the body, taking a bite is like getting a gentle sedative. Then the pain caused by the second bite is perceived by the brain and stimulates the body to release more endorphins. The continuous release of this substance will make the human body in an intoxicating feeling.
This is the wonder of pepper.
These are the reasons why the more you eat, the hotter you get, the more enjoyable you get until you can't stand it.