Being sad about something or not does not change the facts of reality as it is. there are facts, naturally, that cause sad feelings. tragedies in the world, such as massacars in gaza, or little personal crisis, like having to let go ones not-any-more-teacher. But things are happening - with or without us wanting, liking it - to everyone, because everyone has his/her own karma and everyone has to deal with it. Unless one is an arahant. But who of us is?
Therefore, phalayani, and all who want to know, listen carefully to this.
Sadness is just a feeling and when for ever what reason it arises, we should note that it has arisen and should take good care that we do not get overwhelmed by feelings. Vedana anicca, vedana anatta. Feelings are changing, unstable, feelings are without a self.
I was sad often enough in this life, to know that it's never lasting forever. It may lie a little relief in being sad and crying for a while, but then we should face the present moment again the rising and the falling of the abdomen, sitting, hearing, smelling, ... feeling,[sad still, aha], rising, falling, ... It does not make any sense to cling onto those feelings.
Unless one want to act like a fool and does not notice that the ego, this worm, just tryes to make itself important. "i'm hurt! I'm without any help left alone! I want, i need ... I dont want." shut up little thing, your opinion is not asked.
The greatest service of friendship we can do is to let go in freedom those who wish to go to freedom.