I do believe that if you haven't learnt about sadness, you cannot appreciate happiness.
HAPPINESS, BELIEVE THAT IF YOU HAVEN'T LEARN ABOUT SADNESS
The word 'happiness' would lose its meaning if it were not balanced by sadness.
HAPPINESS, BALANCED BY SADNESS
Everyone chases after happiness, not noticing that happiness is right at their heels.
Happiness is beneficial for the body, but it is grief that develops the powers of the mind.
HAPPINESS, GRIEF THAT DEVELOPS THE POWER OF THE MIND
Success is getting what you want. Happiness is liking what you get.
HAPPINESS, HAPPINESS IS LIKING WHAT YOU GET
Be happy with what you have and are, be generous with both, and you won't have to hunt for happiness.