Why fight a duel to the death?

On the face of it, fighting a duel to the death over an insult seems ridiculous. Why take the chance of dying over mere words? But human beings derive much of their sense of self-worth from the respect and esteem of other humans around them. Many people are so deeply invested in their position in the social hierarchy that death is preferable to disrespect, scorn, and humiliation. Not so strange from that perspective.