Right, but it should be explainable, right?

Do you not think that we have the necessary knowledge needed to explain our behaviors, either our own, or others?

From a purely cause and effect perspective behaviour is entirely explainable:
I was hungry so I ate
It was dark so I switched on the lights
I was an only child so now I am an attention seeker

But from what I understand the root of your questions is 'what drives our behaviours?'. If that is the case then conscious beliefs are only one, potentially small, piece of the puzzle.

I guess its important to understand how we determine what our beliefs are in the first place.

How would you respond if I asked you to tell me your beliefs about a controversial topic such as abortion or gay marriage or immigration?

Would your answer be the same or different if you were narrating this response to your family, or if you were giving an interview on CNN, as opposed to posting it on a discussion board. Or perhaps the determinant is the course of action you take when you find one of this issues at your very own doorstep. Or maybe yet still it is the innermost private thoughts you hold, or even the deep feelings that you do not even know exist within you.

The possibility, and i would suggest, more likely, the probability of contrasting responses in these situations begs the question of which do you take to be your fundamental belief or does such a thing even exist?