The pursuit of happiness for its own sake is a fool’s errand. As a goal it is frivolous and unrealistic—frivolous because happiness is a transient state dependent on many conditions, and unrealistic because life is unpredictable and pain may arise at any time.

All suffering comes from wanting your own happiness.
Complete awakening arises from the intention to help others.
Therefore, exchange completely your happiness
For the suffering of others—this is the practice of a bodhisattva.

Forget about being happy. Put it right out of your mind. When you say to yourself, “I want to be happy,” you are telling yourself that you are not happy, and you start looking for something that will make you feel happy… The harder you try to be happy, the more you reinforce that belief that you are not happy…

If you were to let go of the pursuit of happiness, what would you do? To put it a bit more dramatically, suppose you were told that no matter what you did, you would never be happy. Never. What would you do with your life?

You might pay more attention to others. You might accept them just as they are, rather than looking for ways to get them to conform to your idea of how they should be. You might start relating to life itself, rather than looking to what you get out of it. You might be more willing to engage with what life brings you, with all its ups and downs, rather than always wanting it to be other than it is.

Ken McLeod “Forget Happiness”