I came across narcissism. The idea that you’re smarter than everyone else. Comes from a grandiose sense of self importance. But the truth is most people are smarter than you in some ways and less smart in others, but you’re unable to see it because you’re in this black and white mode where preserving your ego relies on you being the smart guy amongst the idiots.
It’s very common in tech to see this. Maybe because we were all exceptional at maths when we were young and got the idea that meant we were super smart and this compensated for our nerdiness.
I worked with a bunch of physicists and every single one of them was smarter than me at maths and physics, I wasn’t even close. But they sometimes talked about politics and current affairs, which I’m very well read in. I didn’t say anything, but I was shocked at how little they knew and how overconfident they were.
None of those folks were narcissists, thankfully they were lovely people, but for sure it highlighted how poor people were at judging their own expertise in an area.
It’s so easy to dismiss people, criticising is easy, and so hard to see just how stupid you can be yourself.
This may be the colloquial description of how narcissism manifests, but it isn't even close to (and possibly completely opposite) clinical narcissism. The grandiosity isn't so much a belief as it is a "false self" put on to garner caretaking from others. It's not "I got all the toys as a kid, so I deserve more stuff!" but a failure to individuate from caregivers. "Mom (as a tool, not a wholly independent person) came when I cried as a kid, so I need you to lavish attention on me and make me feel better now as an adult. I can't see myself without external input; I only see myself as a reflection through you."
The Little Shaman[1] has been one of the most comprehensive-yet-approachable resources I've found for understanding these kinds of high-conflict personalities. In particular [2-4] are pretty relevant to your question.
[1]: https://www.youtube.com/@thelittleshamanhealing/videos [2]: https://www.youtube.com/watch?v=uJZeXxU7QTg [3]: https://www.youtube.com/watch?v=TokWBgMQIZ4 [4]: https://www.youtube.com/watch?v=e5Hq_xNxrOg