The desire for constant happiness only makes us miserable. Because nothing in life is constant. There is neither absolute happiness nor absolute sadness. There are only the changes in our moods that swing between these two extremes.
At any given moment we’re comparing how we feel to how we felt at another time.. comparing one level of our contentment to another. In this way, those of us who have felt great sadness are best able to feel heightened feelings of happiness after we emotionally heal.

We must know misery to identify times of elation.

The key on a daily basis, nevertheless, is to live your life in full. Experience the highs and the lows, the positives and negatives, and all the moods present in between.
Don’t focus on simply being happy.
Focus on living a well-seasoned life. Focus on achieving completeness. Yes, happiness is part of this completeness, but so is sadness, difficulty, frustration, and failure.
And overcoming these latter points supports your personal growth far more than constant happiness.