Jalapeños produce one of the most evenly divided results of any pizza topping YouGov has tested: 50% love or like them, 44% dislike or hate them, and only 6% have no view. The reason the split is so clean is that capsaicin is not a flavour at all. It binds to the TRPV1 receptor on nerve fibres, depolarising the neuron so that it sends a signal to the brain, and the sensation that arrives is the one associated with excessive heat or abrasive damage: warming, tingling, itching or stinging. Nothing is actually being burned. So eating chilli means receiving a damage signal while knowing there is no damage, and people resolve that contradiction in opposite directions. Some experience it as unpleasant and avoid it; it is common for others to report pleasurable and even euphoric effects, which self-described chiliheads attribute to pain-stimulated endorphin release. Either way the receptor is doing the same thing. Almost no other pizza topping recruits the pain system rather than the taste system, which is why jalapeños can be loved and hated in nearly equal measure with almost nobody shrugging.