I always love bringing up [Ignaz Semmelweiss](https://wikipedia.org/wiki/Ignaz_Semmelweis), the Hungarian physician who advocated for hand washing before germ theory was established, after observing that pregnant mothers were more likely to become infected when they were handled by doctors than by midwives. His fastidiousness made him unpopular though and he was ridiculed as a stickler by his fellow staff. When he refused to drop this theory, his colleagues convinced his wife to commit him to a mental hospital, where he died due to infection from an unsanitary operation.