There is some reason but you have not seen it.
As Thay has said before, sometime the sorrow, the sadness of our parents have been transmitted to you and maybe you have that sorrow and that sadness in you.
You have not created that sadness, that sorrow. But maybe one of your ancestors, one of your parents did not know how to transform that sorrow, that sickness. That is why its still there in you.
So one day if you feel sadness and if you don't know what is the cause of that sadness. And you cry. You may like to breath in mindfully and get in touch with your parents. Get in touch with your ancestors who are in you.
And you say "Dear parents, dear ancestors, this is your sorrow, your sadness. And I am crying in order to help you to suffer less in me."
And if you practice like that, every time you feel sad and you cry and you don't know why and how. And you can practice breathing in an out and recognize that sadness in you and smile to it.
And that way you're happy yourself and you help your parents and your ancestors.
And this is a very simple practice. But it has a great effect. To smile to your sadness.
And I have seen people who are crying and smile at the same time. They are smiling to their own sadness.
This is a very wonderful. It's like a positive energy is taking care of a negative energy.
This is like a brother taking care of a sister.
Your compassion, your joy is a big brother. Your sadness, your sorrow is your younger sister. And big brother is taking care of the young sister.
This is a very beautiful practice.
Not only when we are sad we cry, we can do like that but also when we are angry.
Anger is a younger brother. And when we get angry we should know how to smile to our anger.
Smiling to your anger is a very beautiful practice.
And if you can do that, you will get victory.