Which came first the Chicken or the Egg?

I just used this as a catchy title. But, what I'm really getting at is why do you and I believe what we believe to be true?
Do we believe to be true what we believe entirely because of conditioned response from conception onwards? Or do we believe what we believe because of self discovery along the way?

There is the nature-nuture debate even here. But, I suspect that it is a bit of both. So, nature gives us genetics, parents give us conditioning, school gives us conditioning, Church gives us conditioning, and then it is what we choose to do with it?

One of the most helpful things for me to realize is that every quality we might have has two sides to it. A good side and a bad side (and maybe neutral sides as well). So, you can choose whatever qualities you have to manifest the constructive aspects of those qualities.

For example, I can be extremely stubborn to the death sometimes. But, I can also be determined and loyal to the death to my friends and relatives too.

So, what does this do in my life?

I'm very very careful how I pick my friends because I will usually be loyal to the death to them. So, they have to be worthy of my loyalty in the first place or I am lost in some ways in the process because of how stubborn or Determined I can be.
But, if something is important enough I simply will not give up no matter what. And this also sometimes terrifies people because of this intensity that I am capable of.

I'm very grateful at this point that in my 60s and 70s I am starting to "mellow out" some and take a somewhat different view which is more like, "What's the point of whatever I'm doing if I don't survive it?"
So, this has changed me a lot too. In other words, I try to lengthen my life rather than do as crazy of things that I used to.

For example, at 26 when my son was born I decided to stop rock climbing. A year later one of my friends died Free Climbing at Castle Crags without a rope. So, I knew right away that could have been me if I had kept climbing after my son was born.

One by one, I have given up a lot of things in order to stay alive for my family to the point where I still ski, ride a dualsport motorcycle, go snorkling in Hawaii or wherever and travel the world . But, really crazy stuff like rock climbing I gave up in 1974 so my son could have a father to raise him right.