Babies cry because they can't talk, and its the only way to communicate through sound. (Except those older babies that still use the easy way out to get what they want: their screams and yells to get the attention; mind you, they observe how the adults react to it and realized it a very useful weapon.)
When do people cry?
In all those scientific way of explaning things, go figure.
In extreme sadness or happiness.
Watching movies/situations that triggers your emotions.
Lost of a loved one.
Experiencing something unexpected.
Loss of self-esteem.
In any ways, it's a sign that you're in touch of your emotions.
And when there's too much Ego in you, you start loosing your tears.
Both, in a stark contrast.
Should I cry, or should I not?
Should I be a nice; or should I be nastier like some, they say, "Being nice to others doesn't do you any good."?
But one thing for sure,
I shouldn't assume that everyone in the world are my friends.
And I should stick with that lesson.