Final answer:
Capsaicin in peppers activates the same calcium channels as warm receptors, causing excess stimulation and the perception of pain. People who can tolerate more heat find peppers less painful.
Step-by-step explanation:
Pain is the name given to nociception, which is the neural processing of injurious stimuli in response to tissue damage. Peppers taste "hot" because the protein receptors that bind capsaicin open the same calcium channels that are activated by warm receptors. Excess stimulation of these receptors gives the perception of pain. Thus, people who can tolerate more heat find peppers to be less painful.