John Fletcher Fairchild’s lawman career ended because of a punch in the nose. Seriously. Family lore says Wyatt Earp broke Fairchild’s nose in a Dodge City brawl in the 1870s—the Earp part is unconfirmed, the broken nose was real.
He had terrible headaches for years, even as he served as a deputy in northern Arizona (and helped quell the Pleasant Valley War). But after being elected sheriff of Flagstaff in 1898, things got worse.
Reportedly, Fairchild went insane from the pain and had to resign. He died in 1900.