Generally:

We have a good idea of how neurons interact on a low level; dendritic connections among themselves.

At a higher level, we know the brain regions and how they are connected to one another.

Glial cells are still a bit of a mystery but work is advancing rapidly on that front.

I see.

Humans are composed of cells.

Socities are composed of humans.

Now we know everything about how they work!

Umm ... :)

And the whole slew of chemicals flying around that effect pretty much every interaction in the entire system.

I second what EGreg said. You have the additional problem that "brain regions" aren't composed of cells, they're composed of circuits, and neurons themselves come in multiple kinds that have different roles in neural circuits. Then you get the problem that saying, "it's circuits built into regions built out of neurons" doesn't make any predictions about the system as a whole.

So, at the very least, this stratospherically high-level overview is incomplete.