Why must drawing light be so extremely difficult?

I mean, think of it. Different kinds of materials react different when light is directed at them, compared to each other.

The way light effects other obstacles can be extremely different too, depending on the light source,

and don't even get me started on reflections. :|

There are just so many ways light can appear, and none of its appearances is even close to easy to depict.

It drives me crazy, I tell you.