alt Hacker News> I'm envious of those true believer kind of people.
> My father is one of them and he's held absurd ideas as 100% facts and we've had many nasty quarrels about it,
I am not even able to fathom how this is possible; unless someone is trying to convince you to join them in their belief, how on earth does a quarrel arise from differing beliefs?
I'm a lifelong atheist surrounded by religious family (and friends, too, TBH), and the only problem is when they refuse to take subtle hints that I am not interested in reading their book and I have to be blunt with them. And even then, that is not sufficient to start a quarrel!
You're fortunate. Very fortunate.
I've had friends - they really felt like friends at one point - tell me that they don't want to know me anymore when they learned I'm an atheist. One told me that "without God there's no morality", so they can't trust in anything I say. Just like that. One told me that atheists should be branded or marked somehow, so that they can't pose as "good people". To my face. When I mentioned that history knows such policies, and that they almost always lead to massacres, pogroms, and things like the Holocaust, the person didn't see any problem with that. At all.
Beliefs, especially strongly held ones, warp a person and their perception of reality. This influences their actions, and those actions can hit you hard. If a father "100% believes" homosexuals are worse than dirt, and a son firmly believes he loves his boyfriend, that's how a "quarrel" will arise. Most people agree to "live and let live" in principle, but when it comes to details, it's almost always "but we don't want X or Y in this neighborhood".
You're really fortunate to have only met people who hold beliefs that are not in direct opposition to your continued existence in this world or in their presence. However, you need to be aware that there are beliefs that are more incompatible with yours, and that there are people who hold them - and that you will quarrel (or worse - much worse) when you happen to meet.