You will find a blissfulness which contains in it sadness also, because that sadness gives it depth. Watch Buddha's statue - blissful, but still sad. The very word sad gives you wrong connotations - that something is wrong. This is your interpretation. To me, life in its totality is good.
This is a technology where without external input, you create a chemistry of blissfulness within you.
Start with meditation, and things will go on growing in you—silence, serenity, blissfulness, sensitivity. And whatever comes out of meditation, try to bring it out in life. Share it, because everything shared grows fast.
Happiness is one pole, sadness is another. Blissfulness is one pole, misery is another. Life consists of both, and life is richer because of both. A life only of blissfulness will have extension, but will not have depth. A life of only sadness will have depth, but will not have extension.
If you do not choose to become a steady source of blissfulness for yourself and everything around you, you will remain an immature life.