We don’t even understand friction. Which is one source of static charges, which we thus don’t understand well either. And static charges that somehow accumulate in the clouds cause lightning, which… I think you get the point.

It is cool that something so seemingly ordinary is extraordinary.

Not to be flip, but, depending on what "fully" means, we haven't fully understood much of anything about the real world.

Never mind this kind of lightning, it gets really interesting when we start to look at ball lightning, which is very real but rarely sighted.

As a child I saw an acted segment about ball lightning in childrens‘ TV, following a person around the house, and had nightmares for a long time afterwards. The thing is spooky as hell.

As long as you reject the hypothesis of "ionized matter" ball lightning is completely unexplainable. If you accept that ionized matter is hot and gives off plenty of EM radiation, it's pretty simple.