We should never envy the happiness of others just as we would not want them to view us in
the same vein. How is happiness quantified? Who knows the extent of other people's happiness? How do we know whether they are really happy? Are we conjecturing?

Leave others alone. It's totally futile to make any comparison between our state of happiness with that of others.

Let us learn to be content with our happiness however tiny that is. Aren't we lucky not to be living in pain or sorrow?  To wish to have our happiness augmented is indicative of our discontent. A true malaise that would be.

No one can be totally happy neither can we have the same degree of happiness all the time. Our happiness has its ebb and flow and this duality we should always remember.

Happy people also have unhappy days just as unhappy people might have some happy days. Life viewed from this perspective is an alloy of happiness and sorrow.
With that in mind, we can assuredly say that happiness and unhappiness are not mutually exclusive.

If we can understand and accept that life is never perfect, that our happiness is only a contingency as all other aspects of our life are , we would have done away with that which unsettles us and would be a step closer to achieving contentment and tranquillity in our individual life.