Clear.

If all of the universe were made out of transparent substances, what would we see underneath?

Crying.

What's the use of water coming out of your eyes when you're sad?
I mean, think about it.
Does losing liquid make us feel better or something? Sure as hell doesn't make me feel better.
I can understand frowning. Maybe even the sobs.
But the waterworks?! It just seems so weird and unnecessary. I mean, sadness is just an emotion. Why lose bodily fluids over it? "Aww, boohoo, I'm sad, I'm gonna empty myself of all the water in my body through my eyes."
It's ridiculous.