This sin is not really considered to be a sin by those who believe totally in themselves or who or what they believe in. And it’s that totality that makes it dangerous.
At the extreme are zealots and wars. I remember seeing a Simpsons episode where they addressed a controversy as We Are Right (WAR), and that is at the heart of this level of pride. Believing you are the only right one leaves no room for hearing any another opinion or seeing any other perspective.
It’s why there are always extremist views and groups infringing on everyone and everything. A very controversial example is the abortion issue. Pro-lifers have the right to believe everyone has the right to life, but they have been known to express this belief through violence that includes murder and bombings.
And wars start or continue because each nation or religion believes there is no other supreme being or governmental entity better than theirs. It’s okay to be happy with the way you choose to worship or live in your environment, but again the infringing on others is where pride overexerts itself.
It is healthy to be proud of yourself or others or some things, but it is unhealthy for everyone else when you try to force others to follow your way of thinking and living.