1) The first director that was chosen, Dick Richards, was fired because he wanted to change the movie and make it about a whale.
2) Roy Scheider didn’t believe that the crew would save him if any emergency actually happened. So he hid axes around the boat incase he needed to save himself.
3) If you didn’t know, they used a mechanical shark. One of them was actually lost into the sea during filming.
4) There was a lot of problem with the mechanical shark. So Spielberg had to put more shot of the shark’s perspective since it broke down too much.
5) Robert Shaw and Richard Dreyfuss fought a lot during the set.