Thus saith the LORD,...
I have heard thy prayer,
I have seen thy tears:
behold, I will heal thee...
2 Kings 20:5
"The propensity
to cry emotional tears is uniquely human. Of all the claims to human
exceptionality—consciousness, intelligence, 
innovation—it is the liquid
that falls from our eyes when we are sad, happy, jealous, angry, and
grateful, more than anything else, that we can call ours, and ours
alone.
“What
intrigued me about crying is how few people in the world have been
studying it,” said Lauren Bylsma, an assistant professor of psychiatry
and psychology.
There
are three kinds of tears: basal tears, reflexive tears, and emotional
tears.
---Basal tears moisten and protect the eyes from tiny particles.
---Reflexive tears are produced at higher volumes when larger particles or
other irritants enter the eyes, even bright light.
---Emotional tears are produced in the absence of a physical irritant
but in response to a wide variety of emotional states.
“If it was just about removing toxins, leaking out of your eyes a bit is not going to do anything,” said Marc Baker. “The amount of things you could actually remove from the body through tears is so minor.”
....the leading explanation for tears: that they signal to others that we need help." Vice