Know that till the definition of “happiness” exists in your life, “sadness” will always be lurking around the corner. Similarly if you think there is something called “success”, then “failure” will exist in your definitions too. If something is “good” for you, then “bad” will also exist.
Realise that anything that gives you pleasure has the power to give you pain. Words such as “high” and “low”, “favourable” and “unfavourable” are just your personal definitions and individual perceptions. They are the cause of all negative emotions, fears and anxiety existing in your heart.
These emotions arise because of the feeling of attachment. Indeed, detachment is the key to making the best of life. You need to realise that everything in life is complete. Have you heard the Shloka:
Purnam Adham Purnam Idham.
purnaath purnam udachyathe
purnasya purnamdhaaya purnamevaavasishyathe
It means that things happen when it’s time and when you are to learn something from the situations. Whatever life gives you is complete for the moment and for the higher lesson for which you have taken birth. This higher lesson is Self-realisation.
Similarly, in the Bhagvat Gita, Lord Krishna tells Arjuna:
yoga-sthaḥ kuru karmāṇi saṅgaṃ tyaktvā dhanañjaya ।
siddhy-asiddhyoḥ samo bhūtvā samatvaṃ yoga ucyate ।
This means that a person must look at both “joy and sorrow” and “success and failure” with the same eye. There is no such thing as “good” nor “bad” and therefore, when the definitions of happiness and sorrow are both dissolved, you will find everlasting joy within, which is your true nature. This joy is expressed in everything that you do because you know that you are part of Life and you are Life itself.
To know more about the Key to Happiness, watch this video:
https://www.youtube.com/watch?v=OkvBskBR_Vo