Usually, people tend to cry when feel sad or glad. And I am one of the people cried because of regret. As far as I remember one time I cried was when my dog died. I cried so hard because I love it so much. It is everything for me. My dog died after ate the oil. I don't know, It went to ate oil from where. But it came back to die at my home. And that's one things that made me cried.