Some feuds start with a petty slight that turns into a war of resentment, betrayal, backstabbing, and animosity that can last for years. Here we learn about ten personal spats that had long-term consequences. Some were instigated by things that might not be petty at all, like when a guy you love marries your rival or a war destroys your business, but that fact that it got our into the public means it got out of control. And when a friendship ends over sincerely-held but disparate beliefs, that's not really petty. Some of these you've heard of, like the Dassler brothers who split their family shoe company because they couldn't get along, and the two paleontologists who turned their rivalry into intense hatred.
This video has a 90-second skippable ad at 4:54. At that point, I had to abandon the closed captions, because they were way ahead of the video. Your mileage may vary.