Years back, I made a life long enemy with a lead that was hired in our team and decided to change everything after his first week. He presented a new project we would be working on, and I kinda embarrassed him when pointed out that he didn't know what he was talking about [0]. Thus we became enemies, but that's ok he is serving life without parole right now.

[0]: https://idiallo.com/blog/become-an-executive-one-promotion-a...