During World War 2, a military recruiter in U.K. mistook “cryptogamist” (algae expert) for “cryptogramist” and sent Geoffrey Tandy to join the code breakers. He wasn't so useful until captured German papers arrived water-logged. With his expertise, the allies were able to salvage them, crack the code, and hasten the victory.
2. In 2003, during a soccer match between Iran and Denmark, an Iranian player mistook a whistle from the crowd as being the referee's half-time signal and picked the ball up with his hands in the penalty area. Danish player Morten Wieghorst missed the resultant penalty on purpose, and Denmark lost 1–0.
3. In 2013, a deaf 45-year-old man named Terrance Ervin Daniels in North Carolina was repeatedly stabbed to death when he was walking down the street, signing to his friend. A gang member mistook their signing conversation for gang signs.
4. In 2012, a father in New Zealand was arrested and taken away from his children for over 8 months after people at a park mistook him kissing his daughter as indecent assault.
5. In 2013, a medical receptionist mistook the line “shooting some b-ball outside of the school” for “shooting people outside of the school” on a teen patient's voicemail message, prompting county-wide school lockdowns.
A pediatrician named Yvette Cloete in Britain was once forced to flee her home after some local residents mistook her job title to mean she was a pedophile and vandalized her home.
7. During the Falklands war, the British Navy mistook whales for submarines and torpedoed them.
8. The battle of the Chosin Reservoir during the Korean War was lost, due to Tootsie Rolls. A code reader mistook the code for mortar shells (“snacks”, they were called), and literally sent hundreds of crates of Tootsie Rolls to the marines who were out of mortar rounds.
9. Wrestling legend Davey Boy Smith, also known as ‘The British Bulldog’ was given his middle name, “Boy”, when his parents mistook ‘middle name’ for ‘gender’ on his birth certificate.
10. During the filming of Leon: The Professional, a robber mistook a scene for actual cops and "gave himself up" to a bunch of paid extras.
Bill Murray only agreed to do "Garfield" because he mistook the movie's writer--Joel Coen--to be that of the Coen Brothers.
12. The Tollund Man, a 2000-year-old corpse found in a Danish bog was so well preserved that those who found it mistook it for a murder victim and called the police.
13. Greek playwright Aeschylus was killed when an eagle mistook his bald head for a rock, and dropped a tortoise on him, thinking its shell would break.
14. Samuel L. Jackson was supposed to have an afro in Pulp Fiction. He was losing his hair so he needed a wig. A PA went to get an Afro-style wig. The PA didn’t know the different between Afro and Jheri curls and bought Jheri curls. Before they were able to return it, Jackson convinced Tarantino to keep it so he ended up wearing Jheri Curls.
15. Halle Berry attended a Star Trek screening and mistook an audience member for Trek's Klingon attorney Michael Dorn. When the man refused to say he was Dorn, Berry became angry, stood up during the movie, screamed and stomped out.
To promote his newest single, Paul McCartney painted "Hey Jude" on the window of a closed boutique store. A Jewish passerby mistook this as anti-Semitic graffiti ("Jude" meaning "Jew" in German) and smashed the window.
17. When Canada minted coins with poppies for Remembrance Day, visiting US contractors mistook them for suspicious nanotechnology and filed espionage reports about them.
18. When Adolf Hitler shot himself, Helmut Christian Goebbels (son of Joseph Goebbels, a German Nazi politician), mistook the sound of the shot for that of a mortar landing nearby, and screamed: "That was a bullseye!"
19. Green Day joined the lineups of both the Lollapalooza festival and Woodstock '94, where the group started an infamous mud fight. During the concert, a security guard mistook bassist Mike Dirnt for a stage-invading fan and punched out some of his teeth.
20. While the Breaking Bad episode "Half Measures" was being shot, filming was interrupted when a man mistook the character Wendy for a real prostitute and attempted to pick her up.
In 1987, a British tourist named Kris Tait in Tibet nearly had her shirt ripped off by a Chinese policeman because the cop mistook her Phil Silvers 'Sergeant Bilko' t-shirt for an image of the Dalai Lama.
22. In 2012, police tasered a blind man named Colin Farmer because they mistook his guide stick for a samurai sword.
23. In 1902 the congregation at the Shiloh Baptist Church in Alabama mistook a cry of "FIGHT!" for "FIRE!" and stampeded to the exits. 115 people died.
24. When the president of Botswana (Quett Masire) was traveling to Angola for a meeting of African heads of state, the Angolan Air Force mistook his plane for an enemy aircraft and shot it down.
25. When Canada converted to the metric system, Air Canada mistook pounds for kilograms and filled a Boeing 767 with half the fuel needed. The jet was then forced to make a 'dead stick' emergency landing after it ran out fuel mid-air.