The same energy not allowed to move becomes stagnant, stale, creates sadness
Sometimes you may feel very sad, because sadness also belongs to God. Sadness is also divine. There is no necessity to always be happy. Then sadness is your prayer. Then let your heart cry and let your eyes pour down tears. Then let sadness be offered to God. Whatsoever is there in your heart, let it be offered to the Divine Feet - joy or sadness, sometimes even anger.
These are the only two situations possible, and you are in the sad situation. Everybody may know about you - who you are - but you yourself are completely oblivious of your transcendence, of your real nature, of your authentic being. This is the only sadness in life. You can find many excuses, but the real sadness is this: you don't know who you are. How can a person be happy not knowing who he is, not knowing from where he comes, not knowing where he is going? A thousand and one problems arise because of this basic self-ignorance.
Sadness, seriousness are parts of a psychologically sick man - they need causes. So when you are feeling happy, don't start asking, "Why am I happy?" When you are feeling sad ask why you are sad. But strangely, it has become conventional to our minds that when we are sad we accept it as if it is our nature. And when we are joyous even we are surprised; deep inside we even start worrying: "What is happening to me?"
So your life becomes a vital celebration, your relationship becomes a festive thing. Whatsoever you do, every moment is a festival. You eat, and eating becomes a celebration; you take a bath, and bathing becomes a celebration; you talk, and talking becomes a celebration; relationship becomes a celebration. Your outer life becomes festive, there is no sadness in it. How can sadness exist with silence?