Most people like chili peppers, they're hot and spicy, but just what makes them so hot. The answer is Capsaicin (see above) and related molecules that are mostly found in the pithy material surrounding the seeds inside.
Just why are chilis hot anyway you might ask? The answer lies in that the spiciness aids in seed dispersal. How so? What creature (besides humans of course) would bite into a jalapeno and say to itself: hmmm... food! Well, the answer is birds, yes birds. The thing about birds is that their physiology is different. Instead of getting that burning, irritating sensation that humans alone among mammals seem to like, they experience an analgesic effect, probably something like taking codeine, cocaine or maybe even heroin. Anyway, the like it, scoff down the chilis and thus disperse the seeds.
I am disappointed that it's impossible to kill someone with chillis, so I suppose I'll have to stick to torture using them!