Denmark bans noodles for being too hot—what you need to know about chili heat

Chili peppers—love them or hate them, they've got a heat that's hard to ignore. Recently, their fiery nature has even caused a bit of a stir in Denmark, where Buldak Ramen noodles have been banned for being dangerously spicy. So, what's behind the burning sensation we experience when we bite into a chili pepper, and why do some people seek out the masochism of a super hot curry or Korean instant noodles?