Combine the two concepts, Cycles and DUALITY (opposite force manifests together), then man must be aware that in creating happiness, man is indirectly creating — the equal and opposite feeling — sadness. Such is why man will never free man from the feelings of sadness or depression. (This law coincides with Newton’s 3rd law, for every action an equal an opposite reaction.) This concept teaches man that depression is a necessity in our world.
Instead of embracing and connecting with the characteristics of depression, younger civilization of men are more prone to escape and thus hide from these feelings of depression. When we ignore a problem, we allow its energy to grow rampant underneath our very own existence. Life operates on this powerful concept of cycles, and thus, when man runs from a problem, man will never truly liberate man from the problem. In contrary, if man connects & embraces man's feelings of depression and most importantly, smile at the face of man's own depression, then man will have truly liberate man of the benign pains of depression. However, if man persist to ignore man's feelings of depression, by means of suppression or ignorance, then these depressed energy will find other ways to purge themselves in order to restore the balances the Universe desires.
"Your joys are your sorrows unmasked.” (-The Prophet, by Khalil Gibran) In summary, the forces indirectly created are typically commensurate to the creation of the opposite feeling. However, man uniquely contains and stores energies based on man's ability or inability to purge them. That is why man will experience many degrees of depression, leading man to believe man is uniquely in turmoil and that no other man is going through the exact same cycles of joys and sorrows.
All joyous beings, one point or another, will inevitably suffer depression.
When one is further aware of the dualistic creative relationship between polar opposites, one would find it easier to mitigate oneself of depression, by the use of work and sacrifice. Work allows man to purge man of any feelings of defeat and depletedness. Work and sacrifice, are the two forces that are the backbone of man’s ability to manifest that which man desire — and man is commonly known to desire that which man believes delivers man some form of happiness or euphoria. This is the sole reason why all SCRIPTURES embodies the virtues of sacrifices in their teachings. On the polar end, euphoria is a feeling that sits at the pinnacle of the happiness ladder. Right above it is Nirvana, a feeling that is so high up on the scale that it is often time described as the feeling of nothingness, or the absolutely void (where nothing else matters). My point here is that you cannot escape the laws of contrast (aka dualistic creations). If you need further proof that Sacrifices do indeed create manifestations, then I suggest you all read into BLACK MAGIC.Cheers.